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190 lines
4.4 KiB
190 lines
4.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* Copyright (C) 2010: YOSHIFUJI Hideaki <[email protected]> |
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* Copyright (C) 2015: Linus Lüssing <[email protected]> |
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* |
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* Based on the MLD support added to br_multicast.c by YOSHIFUJI Hideaki. |
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*/ |
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#include <linux/skbuff.h> |
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#include <net/ipv6.h> |
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#include <net/mld.h> |
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#include <net/addrconf.h> |
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#include <net/ip6_checksum.h> |
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static int ipv6_mc_check_ip6hdr(struct sk_buff *skb) |
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{ |
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const struct ipv6hdr *ip6h; |
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unsigned int len; |
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unsigned int offset = skb_network_offset(skb) + sizeof(*ip6h); |
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if (!pskb_may_pull(skb, offset)) |
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return -EINVAL; |
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ip6h = ipv6_hdr(skb); |
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if (ip6h->version != 6) |
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return -EINVAL; |
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len = offset + ntohs(ip6h->payload_len); |
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if (skb->len < len || len <= offset) |
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return -EINVAL; |
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skb_set_transport_header(skb, offset); |
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return 0; |
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} |
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static int ipv6_mc_check_exthdrs(struct sk_buff *skb) |
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{ |
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const struct ipv6hdr *ip6h; |
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int offset; |
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u8 nexthdr; |
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__be16 frag_off; |
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ip6h = ipv6_hdr(skb); |
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if (ip6h->nexthdr != IPPROTO_HOPOPTS) |
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return -ENOMSG; |
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nexthdr = ip6h->nexthdr; |
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offset = skb_network_offset(skb) + sizeof(*ip6h); |
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offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); |
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if (offset < 0) |
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return -EINVAL; |
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if (nexthdr != IPPROTO_ICMPV6) |
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return -ENOMSG; |
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skb_set_transport_header(skb, offset); |
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return 0; |
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} |
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static int ipv6_mc_check_mld_reportv2(struct sk_buff *skb) |
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{ |
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unsigned int len = skb_transport_offset(skb); |
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len += sizeof(struct mld2_report); |
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return ipv6_mc_may_pull(skb, len) ? 0 : -EINVAL; |
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} |
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static int ipv6_mc_check_mld_query(struct sk_buff *skb) |
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{ |
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unsigned int transport_len = ipv6_transport_len(skb); |
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struct mld_msg *mld; |
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unsigned int len; |
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/* RFC2710+RFC3810 (MLDv1+MLDv2) require link-local source addresses */ |
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if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) |
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return -EINVAL; |
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/* MLDv1? */ |
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if (transport_len != sizeof(struct mld_msg)) { |
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/* or MLDv2? */ |
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if (transport_len < sizeof(struct mld2_query)) |
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return -EINVAL; |
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len = skb_transport_offset(skb) + sizeof(struct mld2_query); |
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if (!ipv6_mc_may_pull(skb, len)) |
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return -EINVAL; |
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} |
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mld = (struct mld_msg *)skb_transport_header(skb); |
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/* RFC2710+RFC3810 (MLDv1+MLDv2) require the multicast link layer |
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* all-nodes destination address (ff02::1) for general queries |
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*/ |
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if (ipv6_addr_any(&mld->mld_mca) && |
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!ipv6_addr_is_ll_all_nodes(&ipv6_hdr(skb)->daddr)) |
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return -EINVAL; |
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return 0; |
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} |
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static int ipv6_mc_check_mld_msg(struct sk_buff *skb) |
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{ |
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unsigned int len = skb_transport_offset(skb) + sizeof(struct mld_msg); |
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struct mld_msg *mld; |
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if (!ipv6_mc_may_pull(skb, len)) |
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return -ENODATA; |
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mld = (struct mld_msg *)skb_transport_header(skb); |
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switch (mld->mld_type) { |
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case ICMPV6_MGM_REDUCTION: |
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case ICMPV6_MGM_REPORT: |
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return 0; |
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case ICMPV6_MLD2_REPORT: |
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return ipv6_mc_check_mld_reportv2(skb); |
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case ICMPV6_MGM_QUERY: |
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return ipv6_mc_check_mld_query(skb); |
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default: |
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return -ENODATA; |
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} |
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} |
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static inline __sum16 ipv6_mc_validate_checksum(struct sk_buff *skb) |
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{ |
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return skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo); |
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} |
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static int ipv6_mc_check_icmpv6(struct sk_buff *skb) |
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{ |
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unsigned int len = skb_transport_offset(skb) + sizeof(struct icmp6hdr); |
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unsigned int transport_len = ipv6_transport_len(skb); |
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struct sk_buff *skb_chk; |
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if (!ipv6_mc_may_pull(skb, len)) |
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return -EINVAL; |
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skb_chk = skb_checksum_trimmed(skb, transport_len, |
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ipv6_mc_validate_checksum); |
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if (!skb_chk) |
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return -EINVAL; |
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if (skb_chk != skb) |
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kfree_skb(skb_chk); |
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return 0; |
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} |
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/** |
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* ipv6_mc_check_mld - checks whether this is a sane MLD packet |
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* @skb: the skb to validate |
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* |
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* Checks whether an IPv6 packet is a valid MLD packet. If so sets |
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* skb transport header accordingly and returns zero. |
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* |
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* -EINVAL: A broken packet was detected, i.e. it violates some internet |
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* standard |
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* -ENOMSG: IP header validation succeeded but it is not an ICMPv6 packet |
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* with a hop-by-hop option. |
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* -ENODATA: IP+ICMPv6 header with hop-by-hop option validation succeeded |
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* but it is not an MLD packet. |
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* -ENOMEM: A memory allocation failure happened. |
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* |
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* Caller needs to set the skb network header and free any returned skb if it |
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* differs from the provided skb. |
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*/ |
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int ipv6_mc_check_mld(struct sk_buff *skb) |
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{ |
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int ret; |
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ret = ipv6_mc_check_ip6hdr(skb); |
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if (ret < 0) |
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return ret; |
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ret = ipv6_mc_check_exthdrs(skb); |
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if (ret < 0) |
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return ret; |
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ret = ipv6_mc_check_icmpv6(skb); |
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if (ret < 0) |
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return ret; |
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return ipv6_mc_check_mld_msg(skb); |
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} |
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EXPORT_SYMBOL(ipv6_mc_check_mld);
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