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1514 lines
42 KiB
1514 lines
42 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* Multipath TCP |
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* |
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* Copyright (c) 2017 - 2019, Intel Corporation. |
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*/ |
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|
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#define pr_fmt(fmt) "MPTCP: " fmt |
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|
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#include <linux/kernel.h> |
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#include <crypto/sha2.h> |
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#include <net/tcp.h> |
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#include <net/mptcp.h> |
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#include "protocol.h" |
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#include "mib.h" |
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#include <trace/events/mptcp.h> |
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static bool mptcp_cap_flag_sha256(u8 flags) |
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{ |
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return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256; |
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} |
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static void mptcp_parse_option(const struct sk_buff *skb, |
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const unsigned char *ptr, int opsize, |
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struct mptcp_options_received *mp_opt) |
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{ |
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u8 subtype = *ptr >> 4; |
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int expected_opsize; |
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u8 version; |
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u8 flags; |
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u8 i; |
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switch (subtype) { |
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case MPTCPOPT_MP_CAPABLE: |
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/* strict size checking */ |
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if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) { |
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if (skb->len > tcp_hdr(skb)->doff << 2) |
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expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA; |
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else |
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expected_opsize = TCPOLEN_MPTCP_MPC_ACK; |
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} else { |
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if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK) |
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expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK; |
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else |
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expected_opsize = TCPOLEN_MPTCP_MPC_SYN; |
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} |
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/* Cfr RFC 8684 Section 3.3.0: |
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* If a checksum is present but its use had |
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* not been negotiated in the MP_CAPABLE handshake, the receiver MUST |
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* close the subflow with a RST, as it is not behaving as negotiated. |
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* If a checksum is not present when its use has been negotiated, the |
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* receiver MUST close the subflow with a RST, as it is considered |
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* broken |
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* We parse even option with mismatching csum presence, so that |
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* later in subflow_data_ready we can trigger the reset. |
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*/ |
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if (opsize != expected_opsize && |
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(expected_opsize != TCPOLEN_MPTCP_MPC_ACK_DATA || |
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opsize != TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM)) |
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break; |
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|
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/* try to be gentle vs future versions on the initial syn */ |
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version = *ptr++ & MPTCP_VERSION_MASK; |
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if (opsize != TCPOLEN_MPTCP_MPC_SYN) { |
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if (version != MPTCP_SUPPORTED_VERSION) |
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break; |
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} else if (version < MPTCP_SUPPORTED_VERSION) { |
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break; |
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} |
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flags = *ptr++; |
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if (!mptcp_cap_flag_sha256(flags) || |
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(flags & MPTCP_CAP_EXTENSIBILITY)) |
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break; |
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/* RFC 6824, Section 3.1: |
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* "For the Checksum Required bit (labeled "A"), if either |
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* host requires the use of checksums, checksums MUST be used. |
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* In other words, the only way for checksums not to be used |
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* is if both hosts in their SYNs set A=0." |
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*/ |
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if (flags & MPTCP_CAP_CHECKSUM_REQD) |
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mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
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mp_opt->deny_join_id0 = !!(flags & MPTCP_CAP_DENY_JOIN_ID0); |
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mp_opt->suboptions |= OPTIONS_MPTCP_MPC; |
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if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) { |
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mp_opt->sndr_key = get_unaligned_be64(ptr); |
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ptr += 8; |
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} |
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if (opsize >= TCPOLEN_MPTCP_MPC_ACK) { |
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mp_opt->rcvr_key = get_unaligned_be64(ptr); |
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ptr += 8; |
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} |
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if (opsize >= TCPOLEN_MPTCP_MPC_ACK_DATA) { |
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/* Section 3.1.: |
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* "the data parameters in a MP_CAPABLE are semantically |
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* equivalent to those in a DSS option and can be used |
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* interchangeably." |
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*/ |
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mp_opt->suboptions |= OPTION_MPTCP_DSS; |
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mp_opt->use_map = 1; |
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mp_opt->mpc_map = 1; |
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mp_opt->data_len = get_unaligned_be16(ptr); |
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ptr += 2; |
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} |
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if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM) { |
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mp_opt->csum = (__force __sum16)get_unaligned_be16(ptr); |
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mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
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ptr += 2; |
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} |
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pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d csum=%u", |
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version, flags, opsize, mp_opt->sndr_key, |
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mp_opt->rcvr_key, mp_opt->data_len, mp_opt->csum); |
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break; |
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|
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case MPTCPOPT_MP_JOIN: |
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mp_opt->suboptions |= OPTIONS_MPTCP_MPJ; |
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if (opsize == TCPOLEN_MPTCP_MPJ_SYN) { |
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mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; |
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mp_opt->join_id = *ptr++; |
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mp_opt->token = get_unaligned_be32(ptr); |
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ptr += 4; |
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mp_opt->nonce = get_unaligned_be32(ptr); |
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ptr += 4; |
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pr_debug("MP_JOIN bkup=%u, id=%u, token=%u, nonce=%u", |
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mp_opt->backup, mp_opt->join_id, |
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mp_opt->token, mp_opt->nonce); |
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} else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) { |
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mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; |
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mp_opt->join_id = *ptr++; |
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mp_opt->thmac = get_unaligned_be64(ptr); |
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ptr += 8; |
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mp_opt->nonce = get_unaligned_be32(ptr); |
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ptr += 4; |
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pr_debug("MP_JOIN bkup=%u, id=%u, thmac=%llu, nonce=%u", |
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mp_opt->backup, mp_opt->join_id, |
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mp_opt->thmac, mp_opt->nonce); |
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} else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) { |
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ptr += 2; |
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memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN); |
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pr_debug("MP_JOIN hmac"); |
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} else { |
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mp_opt->suboptions &= ~OPTIONS_MPTCP_MPJ; |
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} |
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break; |
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|
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case MPTCPOPT_DSS: |
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pr_debug("DSS"); |
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ptr++; |
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|
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/* we must clear 'mpc_map' be able to detect MP_CAPABLE |
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* map vs DSS map in mptcp_incoming_options(), and reconstruct |
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* map info accordingly |
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*/ |
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mp_opt->mpc_map = 0; |
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flags = (*ptr++) & MPTCP_DSS_FLAG_MASK; |
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mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0; |
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mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0; |
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mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0; |
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mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0; |
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mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK); |
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pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d", |
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mp_opt->data_fin, mp_opt->dsn64, |
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mp_opt->use_map, mp_opt->ack64, |
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mp_opt->use_ack); |
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expected_opsize = TCPOLEN_MPTCP_DSS_BASE; |
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if (mp_opt->use_ack) { |
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if (mp_opt->ack64) |
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expected_opsize += TCPOLEN_MPTCP_DSS_ACK64; |
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else |
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expected_opsize += TCPOLEN_MPTCP_DSS_ACK32; |
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} |
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if (mp_opt->use_map) { |
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if (mp_opt->dsn64) |
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expected_opsize += TCPOLEN_MPTCP_DSS_MAP64; |
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else |
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expected_opsize += TCPOLEN_MPTCP_DSS_MAP32; |
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} |
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/* Always parse any csum presence combination, we will enforce |
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* RFC 8684 Section 3.3.0 checks later in subflow_data_ready |
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*/ |
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if (opsize != expected_opsize && |
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opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) |
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break; |
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mp_opt->suboptions |= OPTION_MPTCP_DSS; |
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if (mp_opt->use_ack) { |
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if (mp_opt->ack64) { |
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mp_opt->data_ack = get_unaligned_be64(ptr); |
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ptr += 8; |
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} else { |
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mp_opt->data_ack = get_unaligned_be32(ptr); |
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ptr += 4; |
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} |
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pr_debug("data_ack=%llu", mp_opt->data_ack); |
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} |
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if (mp_opt->use_map) { |
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if (mp_opt->dsn64) { |
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mp_opt->data_seq = get_unaligned_be64(ptr); |
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ptr += 8; |
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} else { |
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mp_opt->data_seq = get_unaligned_be32(ptr); |
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ptr += 4; |
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} |
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mp_opt->subflow_seq = get_unaligned_be32(ptr); |
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ptr += 4; |
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mp_opt->data_len = get_unaligned_be16(ptr); |
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ptr += 2; |
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if (opsize == expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) { |
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mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
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mp_opt->csum = (__force __sum16)get_unaligned_be16(ptr); |
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ptr += 2; |
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} |
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pr_debug("data_seq=%llu subflow_seq=%u data_len=%u csum=%d:%u", |
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mp_opt->data_seq, mp_opt->subflow_seq, |
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mp_opt->data_len, !!(mp_opt->suboptions & OPTION_MPTCP_CSUMREQD), |
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mp_opt->csum); |
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} |
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break; |
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case MPTCPOPT_ADD_ADDR: |
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mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO; |
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if (!mp_opt->echo) { |
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if (opsize == TCPOLEN_MPTCP_ADD_ADDR || |
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opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT) |
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mp_opt->addr.family = AF_INET; |
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#if IS_ENABLED(CONFIG_MPTCP_IPV6) |
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else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 || |
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opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT) |
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mp_opt->addr.family = AF_INET6; |
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#endif |
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else |
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break; |
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} else { |
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if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE || |
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opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) |
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mp_opt->addr.family = AF_INET; |
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#if IS_ENABLED(CONFIG_MPTCP_IPV6) |
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else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE || |
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opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) |
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mp_opt->addr.family = AF_INET6; |
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#endif |
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else |
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break; |
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} |
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mp_opt->suboptions |= OPTION_MPTCP_ADD_ADDR; |
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mp_opt->addr.id = *ptr++; |
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mp_opt->addr.port = 0; |
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mp_opt->ahmac = 0; |
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if (mp_opt->addr.family == AF_INET) { |
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memcpy((u8 *)&mp_opt->addr.addr.s_addr, (u8 *)ptr, 4); |
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ptr += 4; |
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if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT || |
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opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) { |
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mp_opt->addr.port = htons(get_unaligned_be16(ptr)); |
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ptr += 2; |
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} |
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} |
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#if IS_ENABLED(CONFIG_MPTCP_IPV6) |
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else { |
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memcpy(mp_opt->addr.addr6.s6_addr, (u8 *)ptr, 16); |
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ptr += 16; |
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if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT || |
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opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) { |
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mp_opt->addr.port = htons(get_unaligned_be16(ptr)); |
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ptr += 2; |
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} |
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} |
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#endif |
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if (!mp_opt->echo) { |
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mp_opt->ahmac = get_unaligned_be64(ptr); |
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ptr += 8; |
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} |
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pr_debug("ADD_ADDR%s: id=%d, ahmac=%llu, echo=%d, port=%d", |
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(mp_opt->addr.family == AF_INET6) ? "6" : "", |
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mp_opt->addr.id, mp_opt->ahmac, mp_opt->echo, ntohs(mp_opt->addr.port)); |
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break; |
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case MPTCPOPT_RM_ADDR: |
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if (opsize < TCPOLEN_MPTCP_RM_ADDR_BASE + 1 || |
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opsize > TCPOLEN_MPTCP_RM_ADDR_BASE + MPTCP_RM_IDS_MAX) |
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break; |
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ptr++; |
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|
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mp_opt->suboptions |= OPTION_MPTCP_RM_ADDR; |
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mp_opt->rm_list.nr = opsize - TCPOLEN_MPTCP_RM_ADDR_BASE; |
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for (i = 0; i < mp_opt->rm_list.nr; i++) |
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mp_opt->rm_list.ids[i] = *ptr++; |
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pr_debug("RM_ADDR: rm_list_nr=%d", mp_opt->rm_list.nr); |
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break; |
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|
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case MPTCPOPT_MP_PRIO: |
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if (opsize != TCPOLEN_MPTCP_PRIO) |
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break; |
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|
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mp_opt->suboptions |= OPTION_MPTCP_PRIO; |
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mp_opt->backup = *ptr++ & MPTCP_PRIO_BKUP; |
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pr_debug("MP_PRIO: prio=%d", mp_opt->backup); |
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break; |
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|
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case MPTCPOPT_MP_FASTCLOSE: |
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if (opsize != TCPOLEN_MPTCP_FASTCLOSE) |
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break; |
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ptr += 2; |
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mp_opt->rcvr_key = get_unaligned_be64(ptr); |
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ptr += 8; |
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mp_opt->suboptions |= OPTION_MPTCP_FASTCLOSE; |
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break; |
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case MPTCPOPT_RST: |
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if (opsize != TCPOLEN_MPTCP_RST) |
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break; |
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if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) |
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break; |
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mp_opt->suboptions |= OPTION_MPTCP_RST; |
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flags = *ptr++; |
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mp_opt->reset_transient = flags & MPTCP_RST_TRANSIENT; |
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mp_opt->reset_reason = *ptr; |
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break; |
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case MPTCPOPT_MP_FAIL: |
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if (opsize != TCPOLEN_MPTCP_FAIL) |
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break; |
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ptr += 2; |
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mp_opt->suboptions |= OPTION_MPTCP_FAIL; |
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mp_opt->fail_seq = get_unaligned_be64(ptr); |
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pr_debug("MP_FAIL: data_seq=%llu", mp_opt->fail_seq); |
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break; |
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default: |
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break; |
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} |
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} |
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void mptcp_get_options(const struct sock *sk, |
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const struct sk_buff *skb, |
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struct mptcp_options_received *mp_opt) |
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{ |
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const struct tcphdr *th = tcp_hdr(skb); |
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const unsigned char *ptr; |
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int length; |
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|
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/* initialize option status */ |
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mp_opt->suboptions = 0; |
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length = (th->doff * 4) - sizeof(struct tcphdr); |
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ptr = (const unsigned char *)(th + 1); |
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while (length > 0) { |
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int opcode = *ptr++; |
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int opsize; |
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|
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switch (opcode) { |
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case TCPOPT_EOL: |
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return; |
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case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ |
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length--; |
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continue; |
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default: |
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if (length < 2) |
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return; |
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opsize = *ptr++; |
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if (opsize < 2) /* "silly options" */ |
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return; |
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if (opsize > length) |
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return; /* don't parse partial options */ |
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if (opcode == TCPOPT_MPTCP) |
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mptcp_parse_option(skb, ptr, opsize, mp_opt); |
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ptr += opsize - 2; |
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length -= opsize; |
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} |
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} |
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} |
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bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, |
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unsigned int *size, struct mptcp_out_options *opts) |
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{ |
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
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|
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/* we will use snd_isn to detect first pkt [re]transmission |
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* in mptcp_established_options_mp() |
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*/ |
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subflow->snd_isn = TCP_SKB_CB(skb)->end_seq; |
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if (subflow->request_mptcp) { |
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opts->suboptions = OPTION_MPTCP_MPC_SYN; |
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opts->csum_reqd = mptcp_is_checksum_enabled(sock_net(sk)); |
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opts->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk)); |
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*size = TCPOLEN_MPTCP_MPC_SYN; |
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return true; |
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} else if (subflow->request_join) { |
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pr_debug("remote_token=%u, nonce=%u", subflow->remote_token, |
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subflow->local_nonce); |
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opts->suboptions = OPTION_MPTCP_MPJ_SYN; |
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opts->join_id = subflow->local_id; |
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opts->token = subflow->remote_token; |
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opts->nonce = subflow->local_nonce; |
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opts->backup = subflow->request_bkup; |
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*size = TCPOLEN_MPTCP_MPJ_SYN; |
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return true; |
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} |
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return false; |
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} |
|
|
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/* MP_JOIN client subflow must wait for 4th ack before sending any data: |
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* TCP can't schedule delack timer before the subflow is fully established. |
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* MPTCP uses the delack timer to do 3rd ack retransmissions |
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*/ |
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static void schedule_3rdack_retransmission(struct sock *sk) |
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{ |
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struct inet_connection_sock *icsk = inet_csk(sk); |
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struct tcp_sock *tp = tcp_sk(sk); |
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unsigned long timeout; |
|
|
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/* reschedule with a timeout above RTT, as we must look only for drop */ |
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if (tp->srtt_us) |
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timeout = tp->srtt_us << 1; |
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else |
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timeout = TCP_TIMEOUT_INIT; |
|
|
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WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER); |
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icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; |
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icsk->icsk_ack.timeout = timeout; |
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sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); |
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} |
|
|
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static void clear_3rdack_retransmission(struct sock *sk) |
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{ |
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struct inet_connection_sock *icsk = inet_csk(sk); |
|
|
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sk_stop_timer(sk, &icsk->icsk_delack_timer); |
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icsk->icsk_ack.timeout = 0; |
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icsk->icsk_ack.ato = 0; |
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icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER); |
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} |
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|
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static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, |
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bool snd_data_fin_enable, |
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unsigned int *size, |
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unsigned int remaining, |
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struct mptcp_out_options *opts) |
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{ |
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
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struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
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struct mptcp_ext *mpext; |
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unsigned int data_len; |
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u8 len; |
|
|
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/* When skb is not available, we better over-estimate the emitted |
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* options len. A full DSS option (28 bytes) is longer than |
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* TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so |
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* tell the caller to defer the estimate to |
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* mptcp_established_options_dss(), which will reserve enough space. |
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*/ |
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if (!skb) |
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return false; |
|
|
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/* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */ |
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if (subflow->fully_established || snd_data_fin_enable || |
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subflow->snd_isn != TCP_SKB_CB(skb)->seq || |
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sk->sk_state != TCP_ESTABLISHED) |
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return false; |
|
|
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if (subflow->mp_capable) { |
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mpext = mptcp_get_ext(skb); |
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data_len = mpext ? mpext->data_len : 0; |
|
|
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/* we will check ext_copy.data_len in mptcp_write_options() to |
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* discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and |
|
* TCPOLEN_MPTCP_MPC_ACK |
|
*/ |
|
opts->ext_copy.data_len = data_len; |
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opts->suboptions = OPTION_MPTCP_MPC_ACK; |
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opts->sndr_key = subflow->local_key; |
|
opts->rcvr_key = subflow->remote_key; |
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opts->csum_reqd = READ_ONCE(msk->csum_enabled); |
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opts->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk)); |
|
|
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/* Section 3.1. |
|
* The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK |
|
* packets that start the first subflow of an MPTCP connection, |
|
* as well as the first packet that carries data |
|
*/ |
|
if (data_len > 0) { |
|
len = TCPOLEN_MPTCP_MPC_ACK_DATA; |
|
if (opts->csum_reqd) { |
|
/* we need to propagate more info to csum the pseudo hdr */ |
|
opts->ext_copy.data_seq = mpext->data_seq; |
|
opts->ext_copy.subflow_seq = mpext->subflow_seq; |
|
opts->ext_copy.csum = mpext->csum; |
|
len += TCPOLEN_MPTCP_DSS_CHECKSUM; |
|
} |
|
*size = ALIGN(len, 4); |
|
} else { |
|
*size = TCPOLEN_MPTCP_MPC_ACK; |
|
} |
|
|
|
pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d", |
|
subflow, subflow->local_key, subflow->remote_key, |
|
data_len); |
|
|
|
return true; |
|
} else if (subflow->mp_join) { |
|
opts->suboptions = OPTION_MPTCP_MPJ_ACK; |
|
memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN); |
|
*size = TCPOLEN_MPTCP_MPJ_ACK; |
|
pr_debug("subflow=%p", subflow); |
|
|
|
schedule_3rdack_retransmission(sk); |
|
return true; |
|
} |
|
return false; |
|
} |
|
|
|
static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, |
|
struct sk_buff *skb, struct mptcp_ext *ext) |
|
{ |
|
/* The write_seq value has already been incremented, so the actual |
|
* sequence number for the DATA_FIN is one less. |
|
*/ |
|
u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1; |
|
|
|
if (!ext->use_map || !skb->len) { |
|
/* RFC6824 requires a DSS mapping with specific values |
|
* if DATA_FIN is set but no data payload is mapped |
|
*/ |
|
ext->data_fin = 1; |
|
ext->use_map = 1; |
|
ext->dsn64 = 1; |
|
ext->data_seq = data_fin_tx_seq; |
|
ext->subflow_seq = 0; |
|
ext->data_len = 1; |
|
} else if (ext->data_seq + ext->data_len == data_fin_tx_seq) { |
|
/* If there's an existing DSS mapping and it is the |
|
* final mapping, DATA_FIN consumes 1 additional byte of |
|
* mapping space. |
|
*/ |
|
ext->data_fin = 1; |
|
ext->data_len++; |
|
} |
|
} |
|
|
|
static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, |
|
bool snd_data_fin_enable, |
|
unsigned int *size, |
|
unsigned int remaining, |
|
struct mptcp_out_options *opts) |
|
{ |
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
|
struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
|
unsigned int dss_size = 0; |
|
struct mptcp_ext *mpext; |
|
unsigned int ack_size; |
|
bool ret = false; |
|
u64 ack_seq; |
|
|
|
opts->csum_reqd = READ_ONCE(msk->csum_enabled); |
|
mpext = skb ? mptcp_get_ext(skb) : NULL; |
|
|
|
if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) { |
|
unsigned int map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64; |
|
|
|
if (mpext) { |
|
if (opts->csum_reqd) |
|
map_size += TCPOLEN_MPTCP_DSS_CHECKSUM; |
|
|
|
opts->ext_copy = *mpext; |
|
} |
|
|
|
remaining -= map_size; |
|
dss_size = map_size; |
|
if (skb && snd_data_fin_enable) |
|
mptcp_write_data_fin(subflow, skb, &opts->ext_copy); |
|
opts->suboptions = OPTION_MPTCP_DSS; |
|
ret = true; |
|
} |
|
|
|
/* passive sockets msk will set the 'can_ack' after accept(), even |
|
* if the first subflow may have the already the remote key handy |
|
*/ |
|
opts->ext_copy.use_ack = 0; |
|
if (!READ_ONCE(msk->can_ack)) { |
|
*size = ALIGN(dss_size, 4); |
|
return ret; |
|
} |
|
|
|
ack_seq = READ_ONCE(msk->ack_seq); |
|
if (READ_ONCE(msk->use_64bit_ack)) { |
|
ack_size = TCPOLEN_MPTCP_DSS_ACK64; |
|
opts->ext_copy.data_ack = ack_seq; |
|
opts->ext_copy.ack64 = 1; |
|
} else { |
|
ack_size = TCPOLEN_MPTCP_DSS_ACK32; |
|
opts->ext_copy.data_ack32 = (uint32_t)ack_seq; |
|
opts->ext_copy.ack64 = 0; |
|
} |
|
opts->ext_copy.use_ack = 1; |
|
opts->suboptions = OPTION_MPTCP_DSS; |
|
WRITE_ONCE(msk->old_wspace, __mptcp_space((struct sock *)msk)); |
|
|
|
/* Add kind/length/subtype/flag overhead if mapping is not populated */ |
|
if (dss_size == 0) |
|
ack_size += TCPOLEN_MPTCP_DSS_BASE; |
|
|
|
dss_size += ack_size; |
|
|
|
*size = ALIGN(dss_size, 4); |
|
return true; |
|
} |
|
|
|
static u64 add_addr_generate_hmac(u64 key1, u64 key2, |
|
struct mptcp_addr_info *addr) |
|
{ |
|
u16 port = ntohs(addr->port); |
|
u8 hmac[SHA256_DIGEST_SIZE]; |
|
u8 msg[19]; |
|
int i = 0; |
|
|
|
msg[i++] = addr->id; |
|
if (addr->family == AF_INET) { |
|
memcpy(&msg[i], &addr->addr.s_addr, 4); |
|
i += 4; |
|
} |
|
#if IS_ENABLED(CONFIG_MPTCP_IPV6) |
|
else if (addr->family == AF_INET6) { |
|
memcpy(&msg[i], &addr->addr6.s6_addr, 16); |
|
i += 16; |
|
} |
|
#endif |
|
msg[i++] = port >> 8; |
|
msg[i++] = port & 0xFF; |
|
|
|
mptcp_crypto_hmac_sha(key1, key2, msg, i, hmac); |
|
|
|
return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]); |
|
} |
|
|
|
static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb, |
|
unsigned int *size, |
|
unsigned int remaining, |
|
struct mptcp_out_options *opts) |
|
{ |
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
|
struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
|
bool drop_other_suboptions = false; |
|
unsigned int opt_size = *size; |
|
bool echo; |
|
bool port; |
|
int len; |
|
|
|
/* add addr will strip the existing options, be sure to avoid breaking |
|
* MPC/MPJ handshakes |
|
*/ |
|
if (!mptcp_pm_should_add_signal(msk) || |
|
(opts->suboptions & (OPTION_MPTCP_MPJ_ACK | OPTION_MPTCP_MPC_ACK)) || |
|
!mptcp_pm_add_addr_signal(msk, skb, opt_size, remaining, &opts->addr, |
|
&echo, &port, &drop_other_suboptions)) |
|
return false; |
|
|
|
if (drop_other_suboptions) |
|
remaining += opt_size; |
|
len = mptcp_add_addr_len(opts->addr.family, echo, port); |
|
if (remaining < len) |
|
return false; |
|
|
|
*size = len; |
|
if (drop_other_suboptions) { |
|
pr_debug("drop other suboptions"); |
|
opts->suboptions = 0; |
|
|
|
/* note that e.g. DSS could have written into the memory |
|
* aliased by ahmac, we must reset the field here |
|
* to avoid appending the hmac even for ADD_ADDR echo |
|
* options |
|
*/ |
|
opts->ahmac = 0; |
|
*size -= opt_size; |
|
} |
|
opts->suboptions |= OPTION_MPTCP_ADD_ADDR; |
|
if (!echo) { |
|
opts->ahmac = add_addr_generate_hmac(msk->local_key, |
|
msk->remote_key, |
|
&opts->addr); |
|
} |
|
pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d", |
|
opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port)); |
|
|
|
return true; |
|
} |
|
|
|
static bool mptcp_established_options_rm_addr(struct sock *sk, |
|
unsigned int *size, |
|
unsigned int remaining, |
|
struct mptcp_out_options *opts) |
|
{ |
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
|
struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
|
struct mptcp_rm_list rm_list; |
|
int i, len; |
|
|
|
if (!mptcp_pm_should_rm_signal(msk) || |
|
!(mptcp_pm_rm_addr_signal(msk, remaining, &rm_list))) |
|
return false; |
|
|
|
len = mptcp_rm_addr_len(&rm_list); |
|
if (len < 0) |
|
return false; |
|
if (remaining < len) |
|
return false; |
|
|
|
*size = len; |
|
opts->suboptions |= OPTION_MPTCP_RM_ADDR; |
|
opts->rm_list = rm_list; |
|
|
|
for (i = 0; i < opts->rm_list.nr; i++) |
|
pr_debug("rm_list_ids[%d]=%d", i, opts->rm_list.ids[i]); |
|
|
|
return true; |
|
} |
|
|
|
static bool mptcp_established_options_mp_prio(struct sock *sk, |
|
unsigned int *size, |
|
unsigned int remaining, |
|
struct mptcp_out_options *opts) |
|
{ |
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
|
|
|
/* can't send MP_PRIO with MPC, as they share the same option space: |
|
* 'backup'. Also it makes no sense at all |
|
*/ |
|
if (!subflow->send_mp_prio || |
|
((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | |
|
OPTION_MPTCP_MPC_ACK) & opts->suboptions)) |
|
return false; |
|
|
|
/* account for the trailing 'nop' option */ |
|
if (remaining < TCPOLEN_MPTCP_PRIO_ALIGN) |
|
return false; |
|
|
|
*size = TCPOLEN_MPTCP_PRIO_ALIGN; |
|
opts->suboptions |= OPTION_MPTCP_PRIO; |
|
opts->backup = subflow->request_bkup; |
|
|
|
pr_debug("prio=%d", opts->backup); |
|
|
|
return true; |
|
} |
|
|
|
static noinline bool mptcp_established_options_rst(struct sock *sk, struct sk_buff *skb, |
|
unsigned int *size, |
|
unsigned int remaining, |
|
struct mptcp_out_options *opts) |
|
{ |
|
const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
|
|
|
if (remaining < TCPOLEN_MPTCP_RST) |
|
return false; |
|
|
|
*size = TCPOLEN_MPTCP_RST; |
|
opts->suboptions |= OPTION_MPTCP_RST; |
|
opts->reset_transient = subflow->reset_transient; |
|
opts->reset_reason = subflow->reset_reason; |
|
|
|
return true; |
|
} |
|
|
|
static bool mptcp_established_options_mp_fail(struct sock *sk, |
|
unsigned int *size, |
|
unsigned int remaining, |
|
struct mptcp_out_options *opts) |
|
{ |
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
|
|
|
if (likely(!subflow->send_mp_fail)) |
|
return false; |
|
|
|
if (remaining < TCPOLEN_MPTCP_FAIL) |
|
return false; |
|
|
|
*size = TCPOLEN_MPTCP_FAIL; |
|
opts->suboptions |= OPTION_MPTCP_FAIL; |
|
opts->fail_seq = subflow->map_seq; |
|
|
|
pr_debug("MP_FAIL fail_seq=%llu", opts->fail_seq); |
|
|
|
return true; |
|
} |
|
|
|
bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, |
|
unsigned int *size, unsigned int remaining, |
|
struct mptcp_out_options *opts) |
|
{ |
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
|
struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
|
unsigned int opt_size = 0; |
|
bool snd_data_fin; |
|
bool ret = false; |
|
|
|
opts->suboptions = 0; |
|
|
|
if (unlikely(__mptcp_check_fallback(msk))) |
|
return false; |
|
|
|
if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) { |
|
if (mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) { |
|
*size += opt_size; |
|
remaining -= opt_size; |
|
} |
|
if (mptcp_established_options_rst(sk, skb, &opt_size, remaining, opts)) { |
|
*size += opt_size; |
|
remaining -= opt_size; |
|
} |
|
return true; |
|
} |
|
|
|
snd_data_fin = mptcp_data_fin_enabled(msk); |
|
if (mptcp_established_options_mp(sk, skb, snd_data_fin, &opt_size, remaining, opts)) |
|
ret = true; |
|
else if (mptcp_established_options_dss(sk, skb, snd_data_fin, &opt_size, remaining, opts)) { |
|
ret = true; |
|
if (mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) { |
|
*size += opt_size; |
|
remaining -= opt_size; |
|
return true; |
|
} |
|
} |
|
|
|
/* we reserved enough space for the above options, and exceeding the |
|
* TCP option space would be fatal |
|
*/ |
|
if (WARN_ON_ONCE(opt_size > remaining)) |
|
return false; |
|
|
|
*size += opt_size; |
|
remaining -= opt_size; |
|
if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) { |
|
*size += opt_size; |
|
remaining -= opt_size; |
|
ret = true; |
|
} else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) { |
|
*size += opt_size; |
|
remaining -= opt_size; |
|
ret = true; |
|
} |
|
|
|
if (mptcp_established_options_mp_prio(sk, &opt_size, remaining, opts)) { |
|
*size += opt_size; |
|
remaining -= opt_size; |
|
ret = true; |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, |
|
struct mptcp_out_options *opts) |
|
{ |
|
struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
|
|
|
if (subflow_req->mp_capable) { |
|
opts->suboptions = OPTION_MPTCP_MPC_SYNACK; |
|
opts->sndr_key = subflow_req->local_key; |
|
opts->csum_reqd = subflow_req->csum_reqd; |
|
opts->allow_join_id0 = subflow_req->allow_join_id0; |
|
*size = TCPOLEN_MPTCP_MPC_SYNACK; |
|
pr_debug("subflow_req=%p, local_key=%llu", |
|
subflow_req, subflow_req->local_key); |
|
return true; |
|
} else if (subflow_req->mp_join) { |
|
opts->suboptions = OPTION_MPTCP_MPJ_SYNACK; |
|
opts->backup = subflow_req->backup; |
|
opts->join_id = subflow_req->local_id; |
|
opts->thmac = subflow_req->thmac; |
|
opts->nonce = subflow_req->local_nonce; |
|
pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u", |
|
subflow_req, opts->backup, opts->join_id, |
|
opts->thmac, opts->nonce); |
|
*size = TCPOLEN_MPTCP_MPJ_SYNACK; |
|
return true; |
|
} |
|
return false; |
|
} |
|
|
|
static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, |
|
struct mptcp_subflow_context *subflow, |
|
struct sk_buff *skb, |
|
struct mptcp_options_received *mp_opt) |
|
{ |
|
/* here we can process OoO, in-window pkts, only in-sequence 4th ack |
|
* will make the subflow fully established |
|
*/ |
|
if (likely(subflow->fully_established)) { |
|
/* on passive sockets, check for 3rd ack retransmission |
|
* note that msk is always set by subflow_syn_recv_sock() |
|
* for mp_join subflows |
|
*/ |
|
if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 && |
|
TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq && |
|
subflow->mp_join && (mp_opt->suboptions & OPTIONS_MPTCP_MPJ) && |
|
READ_ONCE(msk->pm.server_side)) |
|
tcp_send_ack(ssk); |
|
goto fully_established; |
|
} |
|
|
|
/* we must process OoO packets before the first subflow is fully |
|
* established. OoO packets are instead a protocol violation |
|
* for MP_JOIN subflows as the peer must not send any data |
|
* before receiving the forth ack - cfr. RFC 8684 section 3.2. |
|
*/ |
|
if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) { |
|
if (subflow->mp_join) |
|
goto reset; |
|
return subflow->mp_capable; |
|
} |
|
|
|
if (((mp_opt->suboptions & OPTION_MPTCP_DSS) && mp_opt->use_ack) || |
|
((mp_opt->suboptions & OPTION_MPTCP_ADD_ADDR) && !mp_opt->echo)) { |
|
/* subflows are fully established as soon as we get any |
|
* additional ack, including ADD_ADDR. |
|
*/ |
|
subflow->fully_established = 1; |
|
WRITE_ONCE(msk->fully_established, true); |
|
goto fully_established; |
|
} |
|
|
|
/* If the first established packet does not contain MP_CAPABLE + data |
|
* then fallback to TCP. Fallback scenarios requires a reset for |
|
* MP_JOIN subflows. |
|
*/ |
|
if (!(mp_opt->suboptions & OPTIONS_MPTCP_MPC)) { |
|
if (subflow->mp_join) |
|
goto reset; |
|
subflow->mp_capable = 0; |
|
pr_fallback(msk); |
|
__mptcp_do_fallback(msk); |
|
return false; |
|
} |
|
|
|
if (mp_opt->deny_join_id0) |
|
WRITE_ONCE(msk->pm.remote_deny_join_id0, true); |
|
|
|
if (unlikely(!READ_ONCE(msk->pm.server_side))) |
|
pr_warn_once("bogus mpc option on established client sk"); |
|
mptcp_subflow_fully_established(subflow, mp_opt); |
|
|
|
fully_established: |
|
/* if the subflow is not already linked into the conn_list, we can't |
|
* notify the PM: this subflow is still on the listener queue |
|
* and the PM possibly acquiring the subflow lock could race with |
|
* the listener close |
|
*/ |
|
if (likely(subflow->pm_notified) || list_empty(&subflow->node)) |
|
return true; |
|
|
|
subflow->pm_notified = 1; |
|
if (subflow->mp_join) { |
|
clear_3rdack_retransmission(ssk); |
|
mptcp_pm_subflow_established(msk); |
|
} else { |
|
mptcp_pm_fully_established(msk, ssk, GFP_ATOMIC); |
|
} |
|
return true; |
|
|
|
reset: |
|
mptcp_subflow_reset(ssk); |
|
return false; |
|
} |
|
|
|
u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq) |
|
{ |
|
u32 old_seq32, cur_seq32; |
|
|
|
old_seq32 = (u32)old_seq; |
|
cur_seq32 = (u32)cur_seq; |
|
cur_seq = (old_seq & GENMASK_ULL(63, 32)) + cur_seq32; |
|
if (unlikely(cur_seq32 < old_seq32 && before(old_seq32, cur_seq32))) |
|
return cur_seq + (1LL << 32); |
|
|
|
/* reverse wrap could happen, too */ |
|
if (unlikely(cur_seq32 > old_seq32 && after(old_seq32, cur_seq32))) |
|
return cur_seq - (1LL << 32); |
|
return cur_seq; |
|
} |
|
|
|
static void ack_update_msk(struct mptcp_sock *msk, |
|
struct sock *ssk, |
|
struct mptcp_options_received *mp_opt) |
|
{ |
|
u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt); |
|
struct sock *sk = (struct sock *)msk; |
|
u64 old_snd_una; |
|
|
|
mptcp_data_lock(sk); |
|
|
|
/* avoid ack expansion on update conflict, to reduce the risk of |
|
* wrongly expanding to a future ack sequence number, which is way |
|
* more dangerous than missing an ack |
|
*/ |
|
old_snd_una = msk->snd_una; |
|
new_snd_una = mptcp_expand_seq(old_snd_una, mp_opt->data_ack, mp_opt->ack64); |
|
|
|
/* ACK for data not even sent yet and even above recovery bound? Ignore.*/ |
|
if (unlikely(after64(new_snd_una, snd_nxt))) { |
|
if (!msk->recovery || after64(new_snd_una, msk->recovery_snd_nxt)) |
|
new_snd_una = old_snd_una; |
|
} |
|
|
|
new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd; |
|
|
|
if (after64(new_wnd_end, msk->wnd_end)) |
|
msk->wnd_end = new_wnd_end; |
|
|
|
/* this assumes mptcp_incoming_options() is invoked after tcp_ack() */ |
|
if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt))) |
|
__mptcp_check_push(sk, ssk); |
|
|
|
if (after64(new_snd_una, old_snd_una)) { |
|
msk->snd_una = new_snd_una; |
|
__mptcp_data_acked(sk); |
|
} |
|
mptcp_data_unlock(sk); |
|
|
|
trace_ack_update_msk(mp_opt->data_ack, |
|
old_snd_una, new_snd_una, |
|
new_wnd_end, msk->wnd_end); |
|
} |
|
|
|
bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit) |
|
{ |
|
/* Skip if DATA_FIN was already received. |
|
* If updating simultaneously with the recvmsg loop, values |
|
* should match. If they mismatch, the peer is misbehaving and |
|
* we will prefer the most recent information. |
|
*/ |
|
if (READ_ONCE(msk->rcv_data_fin)) |
|
return false; |
|
|
|
WRITE_ONCE(msk->rcv_data_fin_seq, |
|
mptcp_expand_seq(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit)); |
|
WRITE_ONCE(msk->rcv_data_fin, 1); |
|
|
|
return true; |
|
} |
|
|
|
static bool add_addr_hmac_valid(struct mptcp_sock *msk, |
|
struct mptcp_options_received *mp_opt) |
|
{ |
|
u64 hmac = 0; |
|
|
|
if (mp_opt->echo) |
|
return true; |
|
|
|
hmac = add_addr_generate_hmac(msk->remote_key, |
|
msk->local_key, |
|
&mp_opt->addr); |
|
|
|
pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n", |
|
msk, (unsigned long long)hmac, |
|
(unsigned long long)mp_opt->ahmac); |
|
|
|
return hmac == mp_opt->ahmac; |
|
} |
|
|
|
/* Return false if a subflow has been reset, else return true */ |
|
bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
|
struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
|
struct mptcp_options_received mp_opt; |
|
struct mptcp_ext *mpext; |
|
|
|
if (__mptcp_check_fallback(msk)) { |
|
/* Keep it simple and unconditionally trigger send data cleanup and |
|
* pending queue spooling. We will need to acquire the data lock |
|
* for more accurate checks, and once the lock is acquired, such |
|
* helpers are cheap. |
|
*/ |
|
mptcp_data_lock(subflow->conn); |
|
if (sk_stream_memory_free(sk)) |
|
__mptcp_check_push(subflow->conn, sk); |
|
__mptcp_data_acked(subflow->conn); |
|
mptcp_data_unlock(subflow->conn); |
|
return true; |
|
} |
|
|
|
mptcp_get_options(sk, skb, &mp_opt); |
|
|
|
/* The subflow can be in close state only if check_fully_established() |
|
* just sent a reset. If so, tell the caller to ignore the current packet. |
|
*/ |
|
if (!check_fully_established(msk, sk, subflow, skb, &mp_opt)) |
|
return sk->sk_state != TCP_CLOSE; |
|
|
|
if (unlikely(mp_opt.suboptions != OPTION_MPTCP_DSS)) { |
|
if ((mp_opt.suboptions & OPTION_MPTCP_FASTCLOSE) && |
|
msk->local_key == mp_opt.rcvr_key) { |
|
WRITE_ONCE(msk->rcv_fastclose, true); |
|
mptcp_schedule_work((struct sock *)msk); |
|
} |
|
|
|
if ((mp_opt.suboptions & OPTION_MPTCP_ADD_ADDR) && |
|
add_addr_hmac_valid(msk, &mp_opt)) { |
|
if (!mp_opt.echo) { |
|
mptcp_pm_add_addr_received(msk, &mp_opt.addr); |
|
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR); |
|
} else { |
|
mptcp_pm_add_addr_echoed(msk, &mp_opt.addr); |
|
mptcp_pm_del_add_timer(msk, &mp_opt.addr, true); |
|
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD); |
|
} |
|
|
|
if (mp_opt.addr.port) |
|
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_PORTADD); |
|
} |
|
|
|
if (mp_opt.suboptions & OPTION_MPTCP_RM_ADDR) |
|
mptcp_pm_rm_addr_received(msk, &mp_opt.rm_list); |
|
|
|
if (mp_opt.suboptions & OPTION_MPTCP_PRIO) { |
|
mptcp_pm_mp_prio_received(sk, mp_opt.backup); |
|
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPPRIORX); |
|
} |
|
|
|
if (mp_opt.suboptions & OPTION_MPTCP_FAIL) { |
|
mptcp_pm_mp_fail_received(sk, mp_opt.fail_seq); |
|
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFAILRX); |
|
} |
|
|
|
if (mp_opt.suboptions & OPTION_MPTCP_RST) { |
|
subflow->reset_seen = 1; |
|
subflow->reset_reason = mp_opt.reset_reason; |
|
subflow->reset_transient = mp_opt.reset_transient; |
|
} |
|
|
|
if (!(mp_opt.suboptions & OPTION_MPTCP_DSS)) |
|
return true; |
|
} |
|
|
|
/* we can't wait for recvmsg() to update the ack_seq, otherwise |
|
* monodirectional flows will stuck |
|
*/ |
|
if (mp_opt.use_ack) |
|
ack_update_msk(msk, sk, &mp_opt); |
|
|
|
/* Zero-data-length packets are dropped by the caller and not |
|
* propagated to the MPTCP layer, so the skb extension does not |
|
* need to be allocated or populated. DATA_FIN information, if |
|
* present, needs to be updated here before the skb is freed. |
|
*/ |
|
if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { |
|
if (mp_opt.data_fin && mp_opt.data_len == 1 && |
|
mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) && |
|
schedule_work(&msk->work)) |
|
sock_hold(subflow->conn); |
|
|
|
return true; |
|
} |
|
|
|
mpext = skb_ext_add(skb, SKB_EXT_MPTCP); |
|
if (!mpext) |
|
return true; |
|
|
|
memset(mpext, 0, sizeof(*mpext)); |
|
|
|
if (likely(mp_opt.use_map)) { |
|
if (mp_opt.mpc_map) { |
|
/* this is an MP_CAPABLE carrying MPTCP data |
|
* we know this map the first chunk of data |
|
*/ |
|
mptcp_crypto_key_sha(subflow->remote_key, NULL, |
|
&mpext->data_seq); |
|
mpext->data_seq++; |
|
mpext->subflow_seq = 1; |
|
mpext->dsn64 = 1; |
|
mpext->mpc_map = 1; |
|
mpext->data_fin = 0; |
|
} else { |
|
mpext->data_seq = mp_opt.data_seq; |
|
mpext->subflow_seq = mp_opt.subflow_seq; |
|
mpext->dsn64 = mp_opt.dsn64; |
|
mpext->data_fin = mp_opt.data_fin; |
|
} |
|
mpext->data_len = mp_opt.data_len; |
|
mpext->use_map = 1; |
|
mpext->csum_reqd = !!(mp_opt.suboptions & OPTION_MPTCP_CSUMREQD); |
|
|
|
if (mpext->csum_reqd) |
|
mpext->csum = mp_opt.csum; |
|
} |
|
|
|
return true; |
|
} |
|
|
|
static void mptcp_set_rwin(const struct tcp_sock *tp) |
|
{ |
|
const struct sock *ssk = (const struct sock *)tp; |
|
const struct mptcp_subflow_context *subflow; |
|
struct mptcp_sock *msk; |
|
u64 ack_seq; |
|
|
|
subflow = mptcp_subflow_ctx(ssk); |
|
msk = mptcp_sk(subflow->conn); |
|
|
|
ack_seq = READ_ONCE(msk->ack_seq) + tp->rcv_wnd; |
|
|
|
if (after64(ack_seq, READ_ONCE(msk->rcv_wnd_sent))) |
|
WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); |
|
} |
|
|
|
static u16 mptcp_make_csum(const struct mptcp_ext *mpext) |
|
{ |
|
struct csum_pseudo_header header; |
|
__wsum csum; |
|
|
|
/* cfr RFC 8684 3.3.1.: |
|
* the data sequence number used in the pseudo-header is |
|
* always the 64-bit value, irrespective of what length is used in the |
|
* DSS option itself. |
|
*/ |
|
header.data_seq = cpu_to_be64(mpext->data_seq); |
|
header.subflow_seq = htonl(mpext->subflow_seq); |
|
header.data_len = htons(mpext->data_len); |
|
header.csum = 0; |
|
|
|
csum = csum_partial(&header, sizeof(header), ~csum_unfold(mpext->csum)); |
|
return (__force u16)csum_fold(csum); |
|
} |
|
|
|
void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, |
|
struct mptcp_out_options *opts) |
|
{ |
|
if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) { |
|
const struct sock *ssk = (const struct sock *)tp; |
|
struct mptcp_subflow_context *subflow; |
|
|
|
subflow = mptcp_subflow_ctx(ssk); |
|
subflow->send_mp_fail = 0; |
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_MP_FAIL, |
|
TCPOLEN_MPTCP_FAIL, |
|
0, 0); |
|
put_unaligned_be64(opts->fail_seq, ptr); |
|
ptr += 2; |
|
} |
|
|
|
/* RST is mutually exclusive with everything else */ |
|
if (unlikely(OPTION_MPTCP_RST & opts->suboptions)) { |
|
*ptr++ = mptcp_option(MPTCPOPT_RST, |
|
TCPOLEN_MPTCP_RST, |
|
opts->reset_transient, |
|
opts->reset_reason); |
|
return; |
|
} |
|
|
|
/* DSS, MPC, MPJ and ADD_ADDR are mutually exclusive, see |
|
* mptcp_established_options*() |
|
*/ |
|
if (likely(OPTION_MPTCP_DSS & opts->suboptions)) { |
|
struct mptcp_ext *mpext = &opts->ext_copy; |
|
u8 len = TCPOLEN_MPTCP_DSS_BASE; |
|
u8 flags = 0; |
|
|
|
if (mpext->use_ack) { |
|
flags = MPTCP_DSS_HAS_ACK; |
|
if (mpext->ack64) { |
|
len += TCPOLEN_MPTCP_DSS_ACK64; |
|
flags |= MPTCP_DSS_ACK64; |
|
} else { |
|
len += TCPOLEN_MPTCP_DSS_ACK32; |
|
} |
|
} |
|
|
|
if (mpext->use_map) { |
|
len += TCPOLEN_MPTCP_DSS_MAP64; |
|
|
|
/* Use only 64-bit mapping flags for now, add |
|
* support for optional 32-bit mappings later. |
|
*/ |
|
flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64; |
|
if (mpext->data_fin) |
|
flags |= MPTCP_DSS_DATA_FIN; |
|
|
|
if (opts->csum_reqd) |
|
len += TCPOLEN_MPTCP_DSS_CHECKSUM; |
|
} |
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags); |
|
|
|
if (mpext->use_ack) { |
|
if (mpext->ack64) { |
|
put_unaligned_be64(mpext->data_ack, ptr); |
|
ptr += 2; |
|
} else { |
|
put_unaligned_be32(mpext->data_ack32, ptr); |
|
ptr += 1; |
|
} |
|
} |
|
|
|
if (mpext->use_map) { |
|
put_unaligned_be64(mpext->data_seq, ptr); |
|
ptr += 2; |
|
put_unaligned_be32(mpext->subflow_seq, ptr); |
|
ptr += 1; |
|
if (opts->csum_reqd) { |
|
put_unaligned_be32(mpext->data_len << 16 | |
|
mptcp_make_csum(mpext), ptr); |
|
} else { |
|
put_unaligned_be32(mpext->data_len << 16 | |
|
TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); |
|
} |
|
} |
|
} else if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | |
|
OPTION_MPTCP_MPC_ACK) & opts->suboptions) { |
|
u8 len, flag = MPTCP_CAP_HMAC_SHA256; |
|
|
|
if (OPTION_MPTCP_MPC_SYN & opts->suboptions) { |
|
len = TCPOLEN_MPTCP_MPC_SYN; |
|
} else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) { |
|
len = TCPOLEN_MPTCP_MPC_SYNACK; |
|
} else if (opts->ext_copy.data_len) { |
|
len = TCPOLEN_MPTCP_MPC_ACK_DATA; |
|
if (opts->csum_reqd) |
|
len += TCPOLEN_MPTCP_DSS_CHECKSUM; |
|
} else { |
|
len = TCPOLEN_MPTCP_MPC_ACK; |
|
} |
|
|
|
if (opts->csum_reqd) |
|
flag |= MPTCP_CAP_CHECKSUM_REQD; |
|
|
|
if (!opts->allow_join_id0) |
|
flag |= MPTCP_CAP_DENY_JOIN_ID0; |
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len, |
|
MPTCP_SUPPORTED_VERSION, |
|
flag); |
|
|
|
if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) & |
|
opts->suboptions)) |
|
goto mp_capable_done; |
|
|
|
put_unaligned_be64(opts->sndr_key, ptr); |
|
ptr += 2; |
|
if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions)) |
|
goto mp_capable_done; |
|
|
|
put_unaligned_be64(opts->rcvr_key, ptr); |
|
ptr += 2; |
|
if (!opts->ext_copy.data_len) |
|
goto mp_capable_done; |
|
|
|
if (opts->csum_reqd) { |
|
put_unaligned_be32(opts->ext_copy.data_len << 16 | |
|
mptcp_make_csum(&opts->ext_copy), ptr); |
|
} else { |
|
put_unaligned_be32(opts->ext_copy.data_len << 16 | |
|
TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); |
|
} |
|
ptr += 1; |
|
|
|
/* MPC is additionally mutually exclusive with MP_PRIO */ |
|
goto mp_capable_done; |
|
} else if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) { |
|
*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, |
|
TCPOLEN_MPTCP_MPJ_SYN, |
|
opts->backup, opts->join_id); |
|
put_unaligned_be32(opts->token, ptr); |
|
ptr += 1; |
|
put_unaligned_be32(opts->nonce, ptr); |
|
ptr += 1; |
|
} else if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) { |
|
*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, |
|
TCPOLEN_MPTCP_MPJ_SYNACK, |
|
opts->backup, opts->join_id); |
|
put_unaligned_be64(opts->thmac, ptr); |
|
ptr += 2; |
|
put_unaligned_be32(opts->nonce, ptr); |
|
ptr += 1; |
|
} else if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) { |
|
*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, |
|
TCPOLEN_MPTCP_MPJ_ACK, 0, 0); |
|
memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN); |
|
ptr += 5; |
|
} else if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) { |
|
u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE; |
|
u8 echo = MPTCP_ADDR_ECHO; |
|
|
|
#if IS_ENABLED(CONFIG_MPTCP_IPV6) |
|
if (opts->addr.family == AF_INET6) |
|
len = TCPOLEN_MPTCP_ADD_ADDR6_BASE; |
|
#endif |
|
|
|
if (opts->addr.port) |
|
len += TCPOLEN_MPTCP_PORT_LEN; |
|
|
|
if (opts->ahmac) { |
|
len += sizeof(opts->ahmac); |
|
echo = 0; |
|
} |
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR, |
|
len, echo, opts->addr.id); |
|
if (opts->addr.family == AF_INET) { |
|
memcpy((u8 *)ptr, (u8 *)&opts->addr.addr.s_addr, 4); |
|
ptr += 1; |
|
} |
|
#if IS_ENABLED(CONFIG_MPTCP_IPV6) |
|
else if (opts->addr.family == AF_INET6) { |
|
memcpy((u8 *)ptr, opts->addr.addr6.s6_addr, 16); |
|
ptr += 4; |
|
} |
|
#endif |
|
|
|
if (!opts->addr.port) { |
|
if (opts->ahmac) { |
|
put_unaligned_be64(opts->ahmac, ptr); |
|
ptr += 2; |
|
} |
|
} else { |
|
u16 port = ntohs(opts->addr.port); |
|
|
|
if (opts->ahmac) { |
|
u8 *bptr = (u8 *)ptr; |
|
|
|
put_unaligned_be16(port, bptr); |
|
bptr += 2; |
|
put_unaligned_be64(opts->ahmac, bptr); |
|
bptr += 8; |
|
put_unaligned_be16(TCPOPT_NOP << 8 | |
|
TCPOPT_NOP, bptr); |
|
|
|
ptr += 3; |
|
} else { |
|
put_unaligned_be32(port << 16 | |
|
TCPOPT_NOP << 8 | |
|
TCPOPT_NOP, ptr); |
|
ptr += 1; |
|
} |
|
} |
|
} |
|
|
|
if (OPTION_MPTCP_PRIO & opts->suboptions) { |
|
const struct sock *ssk = (const struct sock *)tp; |
|
struct mptcp_subflow_context *subflow; |
|
|
|
subflow = mptcp_subflow_ctx(ssk); |
|
subflow->send_mp_prio = 0; |
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_MP_PRIO, |
|
TCPOLEN_MPTCP_PRIO, |
|
opts->backup, TCPOPT_NOP); |
|
} |
|
|
|
mp_capable_done: |
|
if (OPTION_MPTCP_RM_ADDR & opts->suboptions) { |
|
u8 i = 1; |
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_RM_ADDR, |
|
TCPOLEN_MPTCP_RM_ADDR_BASE + opts->rm_list.nr, |
|
0, opts->rm_list.ids[0]); |
|
|
|
while (i < opts->rm_list.nr) { |
|
u8 id1, id2, id3, id4; |
|
|
|
id1 = opts->rm_list.ids[i]; |
|
id2 = i + 1 < opts->rm_list.nr ? opts->rm_list.ids[i + 1] : TCPOPT_NOP; |
|
id3 = i + 2 < opts->rm_list.nr ? opts->rm_list.ids[i + 2] : TCPOPT_NOP; |
|
id4 = i + 3 < opts->rm_list.nr ? opts->rm_list.ids[i + 3] : TCPOPT_NOP; |
|
put_unaligned_be32(id1 << 24 | id2 << 16 | id3 << 8 | id4, ptr); |
|
ptr += 1; |
|
i += 4; |
|
} |
|
} |
|
|
|
if (tp) |
|
mptcp_set_rwin(tp); |
|
} |
|
|
|
__be32 mptcp_get_reset_option(const struct sk_buff *skb) |
|
{ |
|
const struct mptcp_ext *ext = mptcp_get_ext(skb); |
|
u8 flags, reason; |
|
|
|
if (ext) { |
|
flags = ext->reset_transient; |
|
reason = ext->reset_reason; |
|
|
|
return mptcp_option(MPTCPOPT_RST, TCPOLEN_MPTCP_RST, |
|
flags, reason); |
|
} |
|
|
|
return htonl(0u); |
|
} |
|
EXPORT_SYMBOL_GPL(mptcp_get_reset_option);
|
|
|