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1100 lines
29 KiB
1100 lines
29 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* net/dccp/ipv4.c |
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* |
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* An implementation of the DCCP protocol |
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* Arnaldo Carvalho de Melo <[email protected]> |
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*/ |
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|
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#include <linux/dccp.h> |
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#include <linux/icmp.h> |
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#include <linux/slab.h> |
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#include <linux/module.h> |
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#include <linux/skbuff.h> |
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#include <linux/random.h> |
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|
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#include <net/icmp.h> |
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#include <net/inet_common.h> |
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#include <net/inet_hashtables.h> |
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#include <net/inet_sock.h> |
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#include <net/protocol.h> |
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#include <net/sock.h> |
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#include <net/timewait_sock.h> |
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#include <net/tcp_states.h> |
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#include <net/xfrm.h> |
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#include <net/secure_seq.h> |
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#include <net/netns/generic.h> |
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#include "ackvec.h" |
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#include "ccid.h" |
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#include "dccp.h" |
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#include "feat.h" |
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struct dccp_v4_pernet { |
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struct sock *v4_ctl_sk; |
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}; |
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static unsigned int dccp_v4_pernet_id __read_mostly; |
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/* |
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* The per-net v4_ctl_sk socket is used for responding to |
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* the Out-of-the-blue (OOTB) packets. A control sock will be created |
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* for this socket at the initialization time. |
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*/ |
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int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) |
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{ |
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const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; |
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struct inet_sock *inet = inet_sk(sk); |
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struct dccp_sock *dp = dccp_sk(sk); |
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__be16 orig_sport, orig_dport; |
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__be32 daddr, nexthop; |
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struct flowi4 *fl4; |
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struct rtable *rt; |
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int err; |
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struct ip_options_rcu *inet_opt; |
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dp->dccps_role = DCCP_ROLE_CLIENT; |
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if (addr_len < sizeof(struct sockaddr_in)) |
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return -EINVAL; |
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if (usin->sin_family != AF_INET) |
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return -EAFNOSUPPORT; |
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nexthop = daddr = usin->sin_addr.s_addr; |
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inet_opt = rcu_dereference_protected(inet->inet_opt, |
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lockdep_sock_is_held(sk)); |
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if (inet_opt != NULL && inet_opt->opt.srr) { |
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if (daddr == 0) |
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return -EINVAL; |
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nexthop = inet_opt->opt.faddr; |
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} |
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orig_sport = inet->inet_sport; |
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orig_dport = usin->sin_port; |
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fl4 = &inet->cork.fl.u.ip4; |
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rt = ip_route_connect(fl4, nexthop, inet->inet_saddr, |
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sk->sk_bound_dev_if, IPPROTO_DCCP, orig_sport, |
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orig_dport, sk); |
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if (IS_ERR(rt)) |
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return PTR_ERR(rt); |
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if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { |
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ip_rt_put(rt); |
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return -ENETUNREACH; |
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} |
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if (inet_opt == NULL || !inet_opt->opt.srr) |
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daddr = fl4->daddr; |
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if (inet->inet_saddr == 0) { |
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err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET); |
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if (err) { |
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ip_rt_put(rt); |
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return err; |
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} |
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} else { |
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sk_rcv_saddr_set(sk, inet->inet_saddr); |
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} |
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inet->inet_dport = usin->sin_port; |
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sk_daddr_set(sk, daddr); |
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inet_csk(sk)->icsk_ext_hdr_len = 0; |
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if (inet_opt) |
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inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen; |
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/* |
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* Socket identity is still unknown (sport may be zero). |
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* However we set state to DCCP_REQUESTING and not releasing socket |
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* lock select source port, enter ourselves into the hash tables and |
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* complete initialization after this. |
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*/ |
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dccp_set_state(sk, DCCP_REQUESTING); |
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err = inet_hash_connect(&dccp_death_row, sk); |
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if (err != 0) |
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goto failure; |
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rt = ip_route_newports(fl4, rt, orig_sport, orig_dport, |
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inet->inet_sport, inet->inet_dport, sk); |
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if (IS_ERR(rt)) { |
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err = PTR_ERR(rt); |
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rt = NULL; |
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goto failure; |
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} |
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/* OK, now commit destination to socket. */ |
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sk_setup_caps(sk, &rt->dst); |
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dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr, |
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inet->inet_daddr, |
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inet->inet_sport, |
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inet->inet_dport); |
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inet->inet_id = get_random_u16(); |
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err = dccp_connect(sk); |
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rt = NULL; |
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if (err != 0) |
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goto failure; |
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out: |
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return err; |
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failure: |
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/* |
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* This unhashes the socket and releases the local port, if necessary. |
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*/ |
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dccp_set_state(sk, DCCP_CLOSED); |
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inet_bhash2_reset_saddr(sk); |
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ip_rt_put(rt); |
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sk->sk_route_caps = 0; |
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inet->inet_dport = 0; |
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goto out; |
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} |
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EXPORT_SYMBOL_GPL(dccp_v4_connect); |
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/* |
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* This routine does path mtu discovery as defined in RFC1191. |
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*/ |
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static inline void dccp_do_pmtu_discovery(struct sock *sk, |
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const struct iphdr *iph, |
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u32 mtu) |
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{ |
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struct dst_entry *dst; |
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const struct inet_sock *inet = inet_sk(sk); |
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const struct dccp_sock *dp = dccp_sk(sk); |
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/* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs |
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* send out by Linux are always < 576bytes so they should go through |
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* unfragmented). |
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*/ |
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if (sk->sk_state == DCCP_LISTEN) |
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return; |
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dst = inet_csk_update_pmtu(sk, mtu); |
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if (!dst) |
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return; |
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/* Something is about to be wrong... Remember soft error |
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* for the case, if this connection will not able to recover. |
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*/ |
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if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst)) |
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sk->sk_err_soft = EMSGSIZE; |
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mtu = dst_mtu(dst); |
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if (inet->pmtudisc != IP_PMTUDISC_DONT && |
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ip_sk_accept_pmtu(sk) && |
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inet_csk(sk)->icsk_pmtu_cookie > mtu) { |
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dccp_sync_mss(sk, mtu); |
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/* |
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* From RFC 4340, sec. 14.1: |
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* |
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* DCCP-Sync packets are the best choice for upward |
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* probing, since DCCP-Sync probes do not risk application |
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* data loss. |
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*/ |
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dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC); |
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} /* else let the usual retransmit timer handle it */ |
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} |
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static void dccp_do_redirect(struct sk_buff *skb, struct sock *sk) |
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{ |
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struct dst_entry *dst = __sk_dst_check(sk, 0); |
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if (dst) |
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dst->ops->redirect(dst, sk, skb); |
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} |
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void dccp_req_err(struct sock *sk, u64 seq) |
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{ |
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struct request_sock *req = inet_reqsk(sk); |
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struct net *net = sock_net(sk); |
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/* |
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* ICMPs are not backlogged, hence we cannot get an established |
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* socket here. |
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*/ |
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if (!between48(seq, dccp_rsk(req)->dreq_iss, dccp_rsk(req)->dreq_gss)) { |
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__NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); |
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} else { |
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/* |
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* Still in RESPOND, just remove it silently. |
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* There is no good way to pass the error to the newly |
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* created socket, and POSIX does not want network |
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* errors returned from accept(). |
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*/ |
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inet_csk_reqsk_queue_drop(req->rsk_listener, req); |
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} |
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reqsk_put(req); |
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} |
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EXPORT_SYMBOL(dccp_req_err); |
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/* |
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* This routine is called by the ICMP module when it gets some sort of error |
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* condition. If err < 0 then the socket should be closed and the error |
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* returned to the user. If err > 0 it's just the icmp type << 8 | icmp code. |
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* After adjustment header points to the first 8 bytes of the tcp header. We |
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* need to find the appropriate port. |
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* |
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* The locking strategy used here is very "optimistic". When someone else |
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* accesses the socket the ICMP is just dropped and for some paths there is no |
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* check at all. A more general error queue to queue errors for later handling |
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* is probably better. |
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*/ |
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static int dccp_v4_err(struct sk_buff *skb, u32 info) |
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{ |
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const struct iphdr *iph = (struct iphdr *)skb->data; |
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const u8 offset = iph->ihl << 2; |
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const struct dccp_hdr *dh; |
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struct dccp_sock *dp; |
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struct inet_sock *inet; |
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const int type = icmp_hdr(skb)->type; |
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const int code = icmp_hdr(skb)->code; |
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struct sock *sk; |
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__u64 seq; |
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int err; |
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struct net *net = dev_net(skb->dev); |
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/* Only need dccph_dport & dccph_sport which are the first |
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* 4 bytes in dccp header. |
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* Our caller (icmp_socket_deliver()) already pulled 8 bytes for us. |
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*/ |
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BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8); |
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BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8); |
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dh = (struct dccp_hdr *)(skb->data + offset); |
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sk = __inet_lookup_established(net, &dccp_hashinfo, |
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iph->daddr, dh->dccph_dport, |
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iph->saddr, ntohs(dh->dccph_sport), |
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inet_iif(skb), 0); |
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if (!sk) { |
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__ICMP_INC_STATS(net, ICMP_MIB_INERRORS); |
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return -ENOENT; |
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} |
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if (sk->sk_state == DCCP_TIME_WAIT) { |
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inet_twsk_put(inet_twsk(sk)); |
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return 0; |
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} |
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seq = dccp_hdr_seq(dh); |
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if (sk->sk_state == DCCP_NEW_SYN_RECV) { |
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dccp_req_err(sk, seq); |
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return 0; |
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} |
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bh_lock_sock(sk); |
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/* If too many ICMPs get dropped on busy |
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* servers this needs to be solved differently. |
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*/ |
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if (sock_owned_by_user(sk)) |
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__NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); |
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if (sk->sk_state == DCCP_CLOSED) |
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goto out; |
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dp = dccp_sk(sk); |
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if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) && |
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!between48(seq, dp->dccps_awl, dp->dccps_awh)) { |
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__NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); |
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goto out; |
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} |
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switch (type) { |
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case ICMP_REDIRECT: |
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if (!sock_owned_by_user(sk)) |
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dccp_do_redirect(skb, sk); |
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goto out; |
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case ICMP_SOURCE_QUENCH: |
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/* Just silently ignore these. */ |
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goto out; |
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case ICMP_PARAMETERPROB: |
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err = EPROTO; |
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break; |
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case ICMP_DEST_UNREACH: |
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if (code > NR_ICMP_UNREACH) |
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goto out; |
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if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ |
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if (!sock_owned_by_user(sk)) |
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dccp_do_pmtu_discovery(sk, iph, info); |
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goto out; |
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} |
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err = icmp_err_convert[code].errno; |
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break; |
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case ICMP_TIME_EXCEEDED: |
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err = EHOSTUNREACH; |
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break; |
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default: |
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goto out; |
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} |
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switch (sk->sk_state) { |
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case DCCP_REQUESTING: |
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case DCCP_RESPOND: |
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if (!sock_owned_by_user(sk)) { |
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__DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); |
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sk->sk_err = err; |
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sk_error_report(sk); |
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dccp_done(sk); |
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} else |
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sk->sk_err_soft = err; |
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goto out; |
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} |
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/* If we've already connected we will keep trying |
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* until we time out, or the user gives up. |
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* |
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* rfc1122 4.2.3.9 allows to consider as hard errors |
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* only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too, |
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* but it is obsoleted by pmtu discovery). |
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* |
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* Note, that in modern internet, where routing is unreliable |
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* and in each dark corner broken firewalls sit, sending random |
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* errors ordered by their masters even this two messages finally lose |
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* their original sense (even Linux sends invalid PORT_UNREACHs) |
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* |
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* Now we are in compliance with RFCs. |
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* --ANK (980905) |
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*/ |
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inet = inet_sk(sk); |
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if (!sock_owned_by_user(sk) && inet->recverr) { |
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sk->sk_err = err; |
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sk_error_report(sk); |
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} else /* Only an error on timeout */ |
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sk->sk_err_soft = err; |
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out: |
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bh_unlock_sock(sk); |
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sock_put(sk); |
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return 0; |
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} |
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static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb, |
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__be32 src, __be32 dst) |
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{ |
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return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum); |
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} |
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void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb) |
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{ |
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const struct inet_sock *inet = inet_sk(sk); |
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struct dccp_hdr *dh = dccp_hdr(skb); |
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dccp_csum_outgoing(skb); |
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dh->dccph_checksum = dccp_v4_csum_finish(skb, |
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inet->inet_saddr, |
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inet->inet_daddr); |
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} |
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EXPORT_SYMBOL_GPL(dccp_v4_send_check); |
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static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb) |
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{ |
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return secure_dccp_sequence_number(ip_hdr(skb)->daddr, |
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ip_hdr(skb)->saddr, |
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dccp_hdr(skb)->dccph_dport, |
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dccp_hdr(skb)->dccph_sport); |
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} |
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/* |
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* The three way handshake has completed - we got a valid ACK or DATAACK - |
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* now create the new socket. |
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* |
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* This is the equivalent of TCP's tcp_v4_syn_recv_sock |
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*/ |
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struct sock *dccp_v4_request_recv_sock(const struct sock *sk, |
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struct sk_buff *skb, |
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struct request_sock *req, |
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struct dst_entry *dst, |
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struct request_sock *req_unhash, |
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bool *own_req) |
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{ |
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struct inet_request_sock *ireq; |
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struct inet_sock *newinet; |
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struct sock *newsk; |
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|
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if (sk_acceptq_is_full(sk)) |
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goto exit_overflow; |
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newsk = dccp_create_openreq_child(sk, req, skb); |
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if (newsk == NULL) |
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goto exit_nonewsk; |
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newinet = inet_sk(newsk); |
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ireq = inet_rsk(req); |
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sk_daddr_set(newsk, ireq->ir_rmt_addr); |
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sk_rcv_saddr_set(newsk, ireq->ir_loc_addr); |
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newinet->inet_saddr = ireq->ir_loc_addr; |
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RCU_INIT_POINTER(newinet->inet_opt, rcu_dereference(ireq->ireq_opt)); |
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newinet->mc_index = inet_iif(skb); |
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newinet->mc_ttl = ip_hdr(skb)->ttl; |
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newinet->inet_id = get_random_u16(); |
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|
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if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL) |
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goto put_and_exit; |
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|
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sk_setup_caps(newsk, dst); |
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|
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dccp_sync_mss(newsk, dst_mtu(dst)); |
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|
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if (__inet_inherit_port(sk, newsk) < 0) |
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goto put_and_exit; |
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*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), NULL); |
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if (*own_req) |
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ireq->ireq_opt = NULL; |
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else |
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newinet->inet_opt = NULL; |
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return newsk; |
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|
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exit_overflow: |
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__NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); |
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exit_nonewsk: |
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dst_release(dst); |
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exit: |
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__NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); |
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return NULL; |
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put_and_exit: |
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newinet->inet_opt = NULL; |
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inet_csk_prepare_forced_close(newsk); |
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dccp_done(newsk); |
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goto exit; |
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} |
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EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock); |
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|
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static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk, |
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struct sk_buff *skb) |
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{ |
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struct rtable *rt; |
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const struct iphdr *iph = ip_hdr(skb); |
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struct flowi4 fl4 = { |
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.flowi4_oif = inet_iif(skb), |
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.daddr = iph->saddr, |
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.saddr = iph->daddr, |
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.flowi4_tos = RT_CONN_FLAGS(sk), |
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.flowi4_proto = sk->sk_protocol, |
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.fl4_sport = dccp_hdr(skb)->dccph_dport, |
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.fl4_dport = dccp_hdr(skb)->dccph_sport, |
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}; |
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|
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security_skb_classify_flow(skb, flowi4_to_flowi_common(&fl4)); |
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rt = ip_route_output_flow(net, &fl4, sk); |
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if (IS_ERR(rt)) { |
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IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); |
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return NULL; |
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} |
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|
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return &rt->dst; |
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} |
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|
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static int dccp_v4_send_response(const struct sock *sk, struct request_sock *req) |
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{ |
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int err = -1; |
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struct sk_buff *skb; |
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struct dst_entry *dst; |
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struct flowi4 fl4; |
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|
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dst = inet_csk_route_req(sk, &fl4, req); |
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if (dst == NULL) |
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goto out; |
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|
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skb = dccp_make_response(sk, dst, req); |
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if (skb != NULL) { |
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const struct inet_request_sock *ireq = inet_rsk(req); |
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struct dccp_hdr *dh = dccp_hdr(skb); |
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|
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dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->ir_loc_addr, |
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ireq->ir_rmt_addr); |
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rcu_read_lock(); |
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err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, |
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ireq->ir_rmt_addr, |
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rcu_dereference(ireq->ireq_opt), |
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inet_sk(sk)->tos); |
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rcu_read_unlock(); |
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err = net_xmit_eval(err); |
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} |
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|
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out: |
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dst_release(dst); |
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return err; |
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} |
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|
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static void dccp_v4_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb) |
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{ |
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int err; |
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const struct iphdr *rxiph; |
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struct sk_buff *skb; |
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struct dst_entry *dst; |
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struct net *net = dev_net(skb_dst(rxskb)->dev); |
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struct dccp_v4_pernet *pn; |
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struct sock *ctl_sk; |
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|
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/* Never send a reset in response to a reset. */ |
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if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET) |
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return; |
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|
|
if (skb_rtable(rxskb)->rt_type != RTN_LOCAL) |
|
return; |
|
|
|
pn = net_generic(net, dccp_v4_pernet_id); |
|
ctl_sk = pn->v4_ctl_sk; |
|
dst = dccp_v4_route_skb(net, ctl_sk, rxskb); |
|
if (dst == NULL) |
|
return; |
|
|
|
skb = dccp_ctl_make_reset(ctl_sk, rxskb); |
|
if (skb == NULL) |
|
goto out; |
|
|
|
rxiph = ip_hdr(rxskb); |
|
dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr, |
|
rxiph->daddr); |
|
skb_dst_set(skb, dst_clone(dst)); |
|
|
|
local_bh_disable(); |
|
bh_lock_sock(ctl_sk); |
|
err = ip_build_and_send_pkt(skb, ctl_sk, |
|
rxiph->daddr, rxiph->saddr, NULL, |
|
inet_sk(ctl_sk)->tos); |
|
bh_unlock_sock(ctl_sk); |
|
|
|
if (net_xmit_eval(err) == 0) { |
|
__DCCP_INC_STATS(DCCP_MIB_OUTSEGS); |
|
__DCCP_INC_STATS(DCCP_MIB_OUTRSTS); |
|
} |
|
local_bh_enable(); |
|
out: |
|
dst_release(dst); |
|
} |
|
|
|
static void dccp_v4_reqsk_destructor(struct request_sock *req) |
|
{ |
|
dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg); |
|
kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1)); |
|
} |
|
|
|
void dccp_syn_ack_timeout(const struct request_sock *req) |
|
{ |
|
} |
|
EXPORT_SYMBOL(dccp_syn_ack_timeout); |
|
|
|
static struct request_sock_ops dccp_request_sock_ops __read_mostly = { |
|
.family = PF_INET, |
|
.obj_size = sizeof(struct dccp_request_sock), |
|
.rtx_syn_ack = dccp_v4_send_response, |
|
.send_ack = dccp_reqsk_send_ack, |
|
.destructor = dccp_v4_reqsk_destructor, |
|
.send_reset = dccp_v4_ctl_send_reset, |
|
.syn_ack_timeout = dccp_syn_ack_timeout, |
|
}; |
|
|
|
int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
struct inet_request_sock *ireq; |
|
struct request_sock *req; |
|
struct dccp_request_sock *dreq; |
|
const __be32 service = dccp_hdr_request(skb)->dccph_req_service; |
|
struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
|
|
|
/* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */ |
|
if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) |
|
return 0; /* discard, don't send a reset here */ |
|
|
|
if (dccp_bad_service_code(sk, service)) { |
|
dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE; |
|
goto drop; |
|
} |
|
/* |
|
* TW buckets are converted to open requests without |
|
* limitations, they conserve resources and peer is |
|
* evidently real one. |
|
*/ |
|
dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; |
|
if (inet_csk_reqsk_queue_is_full(sk)) |
|
goto drop; |
|
|
|
if (sk_acceptq_is_full(sk)) |
|
goto drop; |
|
|
|
req = inet_reqsk_alloc(&dccp_request_sock_ops, sk, true); |
|
if (req == NULL) |
|
goto drop; |
|
|
|
if (dccp_reqsk_init(req, dccp_sk(sk), skb)) |
|
goto drop_and_free; |
|
|
|
dreq = dccp_rsk(req); |
|
if (dccp_parse_options(sk, dreq, skb)) |
|
goto drop_and_free; |
|
|
|
if (security_inet_conn_request(sk, skb, req)) |
|
goto drop_and_free; |
|
|
|
ireq = inet_rsk(req); |
|
sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr); |
|
sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr); |
|
ireq->ir_mark = inet_request_mark(sk, skb); |
|
ireq->ireq_family = AF_INET; |
|
ireq->ir_iif = READ_ONCE(sk->sk_bound_dev_if); |
|
|
|
/* |
|
* Step 3: Process LISTEN state |
|
* |
|
* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie |
|
* |
|
* Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child(). |
|
*/ |
|
dreq->dreq_isr = dcb->dccpd_seq; |
|
dreq->dreq_gsr = dreq->dreq_isr; |
|
dreq->dreq_iss = dccp_v4_init_sequence(skb); |
|
dreq->dreq_gss = dreq->dreq_iss; |
|
dreq->dreq_service = service; |
|
|
|
if (dccp_v4_send_response(sk, req)) |
|
goto drop_and_free; |
|
|
|
inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT); |
|
reqsk_put(req); |
|
return 0; |
|
|
|
drop_and_free: |
|
reqsk_free(req); |
|
drop: |
|
__DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); |
|
return -1; |
|
} |
|
EXPORT_SYMBOL_GPL(dccp_v4_conn_request); |
|
|
|
int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
struct dccp_hdr *dh = dccp_hdr(skb); |
|
|
|
if (sk->sk_state == DCCP_OPEN) { /* Fast path */ |
|
if (dccp_rcv_established(sk, skb, dh, skb->len)) |
|
goto reset; |
|
return 0; |
|
} |
|
|
|
/* |
|
* Step 3: Process LISTEN state |
|
* If P.type == Request or P contains a valid Init Cookie option, |
|
* (* Must scan the packet's options to check for Init |
|
* Cookies. Only Init Cookies are processed here, |
|
* however; other options are processed in Step 8. This |
|
* scan need only be performed if the endpoint uses Init |
|
* Cookies *) |
|
* (* Generate a new socket and switch to that socket *) |
|
* Set S := new socket for this port pair |
|
* S.state = RESPOND |
|
* Choose S.ISS (initial seqno) or set from Init Cookies |
|
* Initialize S.GAR := S.ISS |
|
* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies |
|
* Continue with S.state == RESPOND |
|
* (* A Response packet will be generated in Step 11 *) |
|
* Otherwise, |
|
* Generate Reset(No Connection) unless P.type == Reset |
|
* Drop packet and return |
|
* |
|
* NOTE: the check for the packet types is done in |
|
* dccp_rcv_state_process |
|
*/ |
|
|
|
if (dccp_rcv_state_process(sk, skb, dh, skb->len)) |
|
goto reset; |
|
return 0; |
|
|
|
reset: |
|
dccp_v4_ctl_send_reset(sk, skb); |
|
kfree_skb(skb); |
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(dccp_v4_do_rcv); |
|
|
|
/** |
|
* dccp_invalid_packet - check for malformed packets |
|
* @skb: Packet to validate |
|
* |
|
* Implements RFC 4340, 8.5: Step 1: Check header basics |
|
* Packets that fail these checks are ignored and do not receive Resets. |
|
*/ |
|
int dccp_invalid_packet(struct sk_buff *skb) |
|
{ |
|
const struct dccp_hdr *dh; |
|
unsigned int cscov; |
|
u8 dccph_doff; |
|
|
|
if (skb->pkt_type != PACKET_HOST) |
|
return 1; |
|
|
|
/* If the packet is shorter than 12 bytes, drop packet and return */ |
|
if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) { |
|
DCCP_WARN("pskb_may_pull failed\n"); |
|
return 1; |
|
} |
|
|
|
dh = dccp_hdr(skb); |
|
|
|
/* If P.type is not understood, drop packet and return */ |
|
if (dh->dccph_type >= DCCP_PKT_INVALID) { |
|
DCCP_WARN("invalid packet type\n"); |
|
return 1; |
|
} |
|
|
|
/* |
|
* If P.Data Offset is too small for packet type, drop packet and return |
|
*/ |
|
dccph_doff = dh->dccph_doff; |
|
if (dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) { |
|
DCCP_WARN("P.Data Offset(%u) too small\n", dccph_doff); |
|
return 1; |
|
} |
|
/* |
|
* If P.Data Offset is too large for packet, drop packet and return |
|
*/ |
|
if (!pskb_may_pull(skb, dccph_doff * sizeof(u32))) { |
|
DCCP_WARN("P.Data Offset(%u) too large\n", dccph_doff); |
|
return 1; |
|
} |
|
dh = dccp_hdr(skb); |
|
/* |
|
* If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet |
|
* has short sequence numbers), drop packet and return |
|
*/ |
|
if ((dh->dccph_type < DCCP_PKT_DATA || |
|
dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) { |
|
DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n", |
|
dccp_packet_name(dh->dccph_type)); |
|
return 1; |
|
} |
|
|
|
/* |
|
* If P.CsCov is too large for the packet size, drop packet and return. |
|
* This must come _before_ checksumming (not as RFC 4340 suggests). |
|
*/ |
|
cscov = dccp_csum_coverage(skb); |
|
if (cscov > skb->len) { |
|
DCCP_WARN("P.CsCov %u exceeds packet length %d\n", |
|
dh->dccph_cscov, skb->len); |
|
return 1; |
|
} |
|
|
|
/* If header checksum is incorrect, drop packet and return. |
|
* (This step is completed in the AF-dependent functions.) */ |
|
skb->csum = skb_checksum(skb, 0, cscov, 0); |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(dccp_invalid_packet); |
|
|
|
/* this is called when real data arrives */ |
|
static int dccp_v4_rcv(struct sk_buff *skb) |
|
{ |
|
const struct dccp_hdr *dh; |
|
const struct iphdr *iph; |
|
bool refcounted; |
|
struct sock *sk; |
|
int min_cov; |
|
|
|
/* Step 1: Check header basics */ |
|
|
|
if (dccp_invalid_packet(skb)) |
|
goto discard_it; |
|
|
|
iph = ip_hdr(skb); |
|
/* Step 1: If header checksum is incorrect, drop packet and return */ |
|
if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) { |
|
DCCP_WARN("dropped packet with invalid checksum\n"); |
|
goto discard_it; |
|
} |
|
|
|
dh = dccp_hdr(skb); |
|
|
|
DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh); |
|
DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type; |
|
|
|
dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu", |
|
dccp_packet_name(dh->dccph_type), |
|
&iph->saddr, ntohs(dh->dccph_sport), |
|
&iph->daddr, ntohs(dh->dccph_dport), |
|
(unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq); |
|
|
|
if (dccp_packet_without_ack(skb)) { |
|
DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ; |
|
dccp_pr_debug_cat("\n"); |
|
} else { |
|
DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb); |
|
dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long) |
|
DCCP_SKB_CB(skb)->dccpd_ack_seq); |
|
} |
|
|
|
lookup: |
|
sk = __inet_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh), |
|
dh->dccph_sport, dh->dccph_dport, 0, &refcounted); |
|
if (!sk) { |
|
dccp_pr_debug("failed to look up flow ID in table and " |
|
"get corresponding socket\n"); |
|
goto no_dccp_socket; |
|
} |
|
|
|
/* |
|
* Step 2: |
|
* ... or S.state == TIMEWAIT, |
|
* Generate Reset(No Connection) unless P.type == Reset |
|
* Drop packet and return |
|
*/ |
|
if (sk->sk_state == DCCP_TIME_WAIT) { |
|
dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n"); |
|
inet_twsk_put(inet_twsk(sk)); |
|
goto no_dccp_socket; |
|
} |
|
|
|
if (sk->sk_state == DCCP_NEW_SYN_RECV) { |
|
struct request_sock *req = inet_reqsk(sk); |
|
struct sock *nsk; |
|
|
|
sk = req->rsk_listener; |
|
if (unlikely(sk->sk_state != DCCP_LISTEN)) { |
|
inet_csk_reqsk_queue_drop_and_put(sk, req); |
|
goto lookup; |
|
} |
|
sock_hold(sk); |
|
refcounted = true; |
|
nsk = dccp_check_req(sk, skb, req); |
|
if (!nsk) { |
|
reqsk_put(req); |
|
goto discard_and_relse; |
|
} |
|
if (nsk == sk) { |
|
reqsk_put(req); |
|
} else if (dccp_child_process(sk, nsk, skb)) { |
|
dccp_v4_ctl_send_reset(sk, skb); |
|
goto discard_and_relse; |
|
} else { |
|
sock_put(sk); |
|
return 0; |
|
} |
|
} |
|
/* |
|
* RFC 4340, sec. 9.2.1: Minimum Checksum Coverage |
|
* o if MinCsCov = 0, only packets with CsCov = 0 are accepted |
|
* o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov |
|
*/ |
|
min_cov = dccp_sk(sk)->dccps_pcrlen; |
|
if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) { |
|
dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n", |
|
dh->dccph_cscov, min_cov); |
|
/* FIXME: "Such packets SHOULD be reported using Data Dropped |
|
* options (Section 11.7) with Drop Code 0, Protocol |
|
* Constraints." */ |
|
goto discard_and_relse; |
|
} |
|
|
|
if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) |
|
goto discard_and_relse; |
|
nf_reset_ct(skb); |
|
|
|
return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, refcounted); |
|
|
|
no_dccp_socket: |
|
if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) |
|
goto discard_it; |
|
/* |
|
* Step 2: |
|
* If no socket ... |
|
* Generate Reset(No Connection) unless P.type == Reset |
|
* Drop packet and return |
|
*/ |
|
if (dh->dccph_type != DCCP_PKT_RESET) { |
|
DCCP_SKB_CB(skb)->dccpd_reset_code = |
|
DCCP_RESET_CODE_NO_CONNECTION; |
|
dccp_v4_ctl_send_reset(sk, skb); |
|
} |
|
|
|
discard_it: |
|
kfree_skb(skb); |
|
return 0; |
|
|
|
discard_and_relse: |
|
if (refcounted) |
|
sock_put(sk); |
|
goto discard_it; |
|
} |
|
|
|
static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = { |
|
.queue_xmit = ip_queue_xmit, |
|
.send_check = dccp_v4_send_check, |
|
.rebuild_header = inet_sk_rebuild_header, |
|
.conn_request = dccp_v4_conn_request, |
|
.syn_recv_sock = dccp_v4_request_recv_sock, |
|
.net_header_len = sizeof(struct iphdr), |
|
.setsockopt = ip_setsockopt, |
|
.getsockopt = ip_getsockopt, |
|
.addr2sockaddr = inet_csk_addr2sockaddr, |
|
.sockaddr_len = sizeof(struct sockaddr_in), |
|
}; |
|
|
|
static int dccp_v4_init_sock(struct sock *sk) |
|
{ |
|
static __u8 dccp_v4_ctl_sock_initialized; |
|
int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized); |
|
|
|
if (err == 0) { |
|
if (unlikely(!dccp_v4_ctl_sock_initialized)) |
|
dccp_v4_ctl_sock_initialized = 1; |
|
inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops; |
|
} |
|
|
|
return err; |
|
} |
|
|
|
static struct timewait_sock_ops dccp_timewait_sock_ops = { |
|
.twsk_obj_size = sizeof(struct inet_timewait_sock), |
|
}; |
|
|
|
static struct proto dccp_v4_prot = { |
|
.name = "DCCP", |
|
.owner = THIS_MODULE, |
|
.close = dccp_close, |
|
.connect = dccp_v4_connect, |
|
.disconnect = dccp_disconnect, |
|
.ioctl = dccp_ioctl, |
|
.init = dccp_v4_init_sock, |
|
.setsockopt = dccp_setsockopt, |
|
.getsockopt = dccp_getsockopt, |
|
.sendmsg = dccp_sendmsg, |
|
.recvmsg = dccp_recvmsg, |
|
.backlog_rcv = dccp_v4_do_rcv, |
|
.hash = inet_hash, |
|
.unhash = inet_unhash, |
|
.accept = inet_csk_accept, |
|
.get_port = inet_csk_get_port, |
|
.shutdown = dccp_shutdown, |
|
.destroy = dccp_destroy_sock, |
|
.orphan_count = &dccp_orphan_count, |
|
.max_header = MAX_DCCP_HEADER, |
|
.obj_size = sizeof(struct dccp_sock), |
|
.slab_flags = SLAB_TYPESAFE_BY_RCU, |
|
.rsk_prot = &dccp_request_sock_ops, |
|
.twsk_prot = &dccp_timewait_sock_ops, |
|
.h.hashinfo = &dccp_hashinfo, |
|
}; |
|
|
|
static const struct net_protocol dccp_v4_protocol = { |
|
.handler = dccp_v4_rcv, |
|
.err_handler = dccp_v4_err, |
|
.no_policy = 1, |
|
.icmp_strict_tag_validation = 1, |
|
}; |
|
|
|
static const struct proto_ops inet_dccp_ops = { |
|
.family = PF_INET, |
|
.owner = THIS_MODULE, |
|
.release = inet_release, |
|
.bind = inet_bind, |
|
.connect = inet_stream_connect, |
|
.socketpair = sock_no_socketpair, |
|
.accept = inet_accept, |
|
.getname = inet_getname, |
|
/* FIXME: work on tcp_poll to rename it to inet_csk_poll */ |
|
.poll = dccp_poll, |
|
.ioctl = inet_ioctl, |
|
.gettstamp = sock_gettstamp, |
|
/* FIXME: work on inet_listen to rename it to sock_common_listen */ |
|
.listen = inet_dccp_listen, |
|
.shutdown = inet_shutdown, |
|
.setsockopt = sock_common_setsockopt, |
|
.getsockopt = sock_common_getsockopt, |
|
.sendmsg = inet_sendmsg, |
|
.recvmsg = sock_common_recvmsg, |
|
.mmap = sock_no_mmap, |
|
.sendpage = sock_no_sendpage, |
|
}; |
|
|
|
static struct inet_protosw dccp_v4_protosw = { |
|
.type = SOCK_DCCP, |
|
.protocol = IPPROTO_DCCP, |
|
.prot = &dccp_v4_prot, |
|
.ops = &inet_dccp_ops, |
|
.flags = INET_PROTOSW_ICSK, |
|
}; |
|
|
|
static int __net_init dccp_v4_init_net(struct net *net) |
|
{ |
|
struct dccp_v4_pernet *pn = net_generic(net, dccp_v4_pernet_id); |
|
|
|
if (dccp_hashinfo.bhash == NULL) |
|
return -ESOCKTNOSUPPORT; |
|
|
|
return inet_ctl_sock_create(&pn->v4_ctl_sk, PF_INET, |
|
SOCK_DCCP, IPPROTO_DCCP, net); |
|
} |
|
|
|
static void __net_exit dccp_v4_exit_net(struct net *net) |
|
{ |
|
struct dccp_v4_pernet *pn = net_generic(net, dccp_v4_pernet_id); |
|
|
|
inet_ctl_sock_destroy(pn->v4_ctl_sk); |
|
} |
|
|
|
static void __net_exit dccp_v4_exit_batch(struct list_head *net_exit_list) |
|
{ |
|
inet_twsk_purge(&dccp_hashinfo, AF_INET); |
|
} |
|
|
|
static struct pernet_operations dccp_v4_ops = { |
|
.init = dccp_v4_init_net, |
|
.exit = dccp_v4_exit_net, |
|
.exit_batch = dccp_v4_exit_batch, |
|
.id = &dccp_v4_pernet_id, |
|
.size = sizeof(struct dccp_v4_pernet), |
|
}; |
|
|
|
static int __init dccp_v4_init(void) |
|
{ |
|
int err = proto_register(&dccp_v4_prot, 1); |
|
|
|
if (err) |
|
goto out; |
|
|
|
inet_register_protosw(&dccp_v4_protosw); |
|
|
|
err = register_pernet_subsys(&dccp_v4_ops); |
|
if (err) |
|
goto out_destroy_ctl_sock; |
|
|
|
err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP); |
|
if (err) |
|
goto out_proto_unregister; |
|
|
|
out: |
|
return err; |
|
out_proto_unregister: |
|
unregister_pernet_subsys(&dccp_v4_ops); |
|
out_destroy_ctl_sock: |
|
inet_unregister_protosw(&dccp_v4_protosw); |
|
proto_unregister(&dccp_v4_prot); |
|
goto out; |
|
} |
|
|
|
static void __exit dccp_v4_exit(void) |
|
{ |
|
inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP); |
|
unregister_pernet_subsys(&dccp_v4_ops); |
|
inet_unregister_protosw(&dccp_v4_protosw); |
|
proto_unregister(&dccp_v4_prot); |
|
} |
|
|
|
module_init(dccp_v4_init); |
|
module_exit(dccp_v4_exit); |
|
|
|
/* |
|
* __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33) |
|
* values directly, Also cover the case where the protocol is not specified, |
|
* i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP |
|
*/ |
|
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6); |
|
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6); |
|
MODULE_LICENSE("GPL"); |
|
MODULE_AUTHOR("Arnaldo Carvalho de Melo <[email protected]>"); |
|
MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");
|
|
|