netfilter: push reasm skb through instead of original frag skbs
Pushing original fragments through causes several problems. For example for matching, frags may not be matched correctly. Take following example: <example> On HOSTA do: ip6tables -I INPUT -p icmpv6 -j DROP ip6tables -I INPUT -p icmpv6 -m icmp6 --icmpv6-type 128 -j ACCEPT and on HOSTB you do: ping6 HOSTA -s2000 (MTU is 1500) Incoming echo requests will be filtered out on HOSTA. This issue does not occur with smaller packets than MTU (where fragmentation does not happen) </example> As was discussed previously, the only correct solution seems to be to use reassembled skb instead of separete frags. Doing this has positive side effects in reducing sk_buff by one pointer (nfct_reasm) and also the reams dances in ipvs and conntrack can be removed. Future plan is to remove net/ipv6/netfilter/nf_conntrack_reasm.c entirely and use code in net/ipv6/reassembly.c instead. Signed-off-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Marcelo Ricardo Leitner <mleitner@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jiri Pirko
David S. Miller
Родитель
9037c3579a
Коммит
6aafeef03b
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@ -337,11 +337,6 @@ typedef unsigned int sk_buff_data_t;
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typedef unsigned char *sk_buff_data_t;
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#endif
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#if defined(CONFIG_NF_DEFRAG_IPV4) || defined(CONFIG_NF_DEFRAG_IPV4_MODULE) || \
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defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE)
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#define NET_SKBUFF_NF_DEFRAG_NEEDED 1
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#endif
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/**
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* struct sk_buff - socket buffer
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* @next: Next buffer in list
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@ -374,7 +369,6 @@ typedef unsigned char *sk_buff_data_t;
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* @protocol: Packet protocol from driver
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* @destructor: Destruct function
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* @nfct: Associated connection, if any
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* @nfct_reasm: netfilter conntrack re-assembly pointer
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* @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
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* @skb_iif: ifindex of device we arrived on
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* @tc_index: Traffic control index
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@ -463,9 +457,6 @@ struct sk_buff {
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
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struct nf_conntrack *nfct;
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#endif
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#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
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struct sk_buff *nfct_reasm;
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#endif
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#ifdef CONFIG_BRIDGE_NETFILTER
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struct nf_bridge_info *nf_bridge;
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#endif
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@ -2595,18 +2586,6 @@ static inline void nf_conntrack_get(struct nf_conntrack *nfct)
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atomic_inc(&nfct->use);
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}
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#endif
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#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
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static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
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{
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if (skb)
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atomic_inc(&skb->users);
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}
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static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
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{
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if (skb)
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kfree_skb(skb);
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}
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#endif
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#ifdef CONFIG_BRIDGE_NETFILTER
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static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
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{
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@ -2625,10 +2604,6 @@ static inline void nf_reset(struct sk_buff *skb)
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nf_conntrack_put(skb->nfct);
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skb->nfct = NULL;
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#endif
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#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
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nf_conntrack_put_reasm(skb->nfct_reasm);
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skb->nfct_reasm = NULL;
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#endif
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#ifdef CONFIG_BRIDGE_NETFILTER
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nf_bridge_put(skb->nf_bridge);
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skb->nf_bridge = NULL;
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@ -2650,10 +2625,6 @@ static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
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nf_conntrack_get(src->nfct);
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dst->nfctinfo = src->nfctinfo;
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#endif
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#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
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dst->nfct_reasm = src->nfct_reasm;
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nf_conntrack_get_reasm(src->nfct_reasm);
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#endif
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#ifdef CONFIG_BRIDGE_NETFILTER
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dst->nf_bridge = src->nf_bridge;
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nf_bridge_get(src->nf_bridge);
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@ -2665,9 +2636,6 @@ static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
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nf_conntrack_put(dst->nfct);
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#endif
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#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
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nf_conntrack_put_reasm(dst->nfct_reasm);
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#endif
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#ifdef CONFIG_BRIDGE_NETFILTER
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nf_bridge_put(dst->nf_bridge);
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#endif
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@ -109,7 +109,6 @@ extern int ip_vs_conn_tab_size;
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struct ip_vs_iphdr {
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__u32 len; /* IPv4 simply where L4 starts
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IPv6 where L4 Transport Header starts */
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__u32 thoff_reasm; /* Transport Header Offset in nfct_reasm skb */
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__u16 fragoffs; /* IPv6 fragment offset, 0 if first frag (or not frag)*/
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__s16 protocol;
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__s32 flags;
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@ -117,34 +116,12 @@ struct ip_vs_iphdr {
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union nf_inet_addr daddr;
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};
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/* Dependency to module: nf_defrag_ipv6 */
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#if defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE)
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static inline struct sk_buff *skb_nfct_reasm(const struct sk_buff *skb)
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{
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return skb->nfct_reasm;
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}
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static inline void *frag_safe_skb_hp(const struct sk_buff *skb, int offset,
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int len, void *buffer,
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const struct ip_vs_iphdr *ipvsh)
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{
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if (unlikely(ipvsh->fragoffs && skb_nfct_reasm(skb)))
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return skb_header_pointer(skb_nfct_reasm(skb),
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ipvsh->thoff_reasm, len, buffer);
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return skb_header_pointer(skb, offset, len, buffer);
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}
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#else
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static inline struct sk_buff *skb_nfct_reasm(const struct sk_buff *skb)
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{
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return NULL;
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}
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static inline void *frag_safe_skb_hp(const struct sk_buff *skb, int offset,
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int len, void *buffer,
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const struct ip_vs_iphdr *ipvsh)
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{
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return skb_header_pointer(skb, offset, len, buffer);
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}
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#endif
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static inline void
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ip_vs_fill_ip4hdr(const void *nh, struct ip_vs_iphdr *iphdr)
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@ -171,19 +148,12 @@ ip_vs_fill_iph_skb(int af, const struct sk_buff *skb, struct ip_vs_iphdr *iphdr)
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(struct ipv6hdr *)skb_network_header(skb);
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iphdr->saddr.in6 = iph->saddr;
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iphdr->daddr.in6 = iph->daddr;
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/* ipv6_find_hdr() updates len, flags, thoff_reasm */
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iphdr->thoff_reasm = 0;
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/* ipv6_find_hdr() updates len, flags */
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iphdr->len = 0;
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iphdr->flags = 0;
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iphdr->protocol = ipv6_find_hdr(skb, &iphdr->len, -1,
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&iphdr->fragoffs,
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&iphdr->flags);
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/* get proto from re-assembled packet and it's offset */
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if (skb_nfct_reasm(skb))
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iphdr->protocol = ipv6_find_hdr(skb_nfct_reasm(skb),
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&iphdr->thoff_reasm,
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-1, NULL, NULL);
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} else
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#endif
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{
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@ -6,9 +6,7 @@ void nf_defrag_ipv6_enable(void);
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int nf_ct_frag6_init(void);
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void nf_ct_frag6_cleanup(void);
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struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user);
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void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
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struct net_device *in, struct net_device *out,
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int (*okfn)(struct sk_buff *));
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void nf_ct_frag6_consume_orig(struct sk_buff *skb);
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struct inet_frags_ctl;
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@ -592,9 +592,6 @@ static void skb_release_head_state(struct sk_buff *skb)
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#if IS_ENABLED(CONFIG_NF_CONNTRACK)
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nf_conntrack_put(skb->nfct);
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#endif
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#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
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nf_conntrack_put_reasm(skb->nfct_reasm);
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#endif
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#ifdef CONFIG_BRIDGE_NETFILTER
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nf_bridge_put(skb->nf_bridge);
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#endif
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@ -169,64 +169,13 @@ out:
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return nf_conntrack_confirm(skb);
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}
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static unsigned int __ipv6_conntrack_in(struct net *net,
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unsigned int hooknum,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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struct sk_buff *reasm = skb->nfct_reasm;
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const struct nf_conn_help *help;
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struct nf_conn *ct;
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enum ip_conntrack_info ctinfo;
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/* This packet is fragmented and has reassembled packet. */
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if (reasm) {
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/* Reassembled packet isn't parsed yet ? */
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if (!reasm->nfct) {
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unsigned int ret;
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ret = nf_conntrack_in(net, PF_INET6, hooknum, reasm);
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if (ret != NF_ACCEPT)
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return ret;
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}
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/* Conntrack helpers need the entire reassembled packet in the
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* POST_ROUTING hook. In case of unconfirmed connections NAT
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* might reassign a helper, so the entire packet is also
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* required.
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*/
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ct = nf_ct_get(reasm, &ctinfo);
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if (ct != NULL && !nf_ct_is_untracked(ct)) {
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help = nfct_help(ct);
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if ((help && help->helper) || !nf_ct_is_confirmed(ct)) {
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nf_conntrack_get_reasm(reasm);
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NF_HOOK_THRESH(NFPROTO_IPV6, hooknum, reasm,
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(struct net_device *)in,
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(struct net_device *)out,
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okfn, NF_IP6_PRI_CONNTRACK + 1);
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return NF_DROP_ERR(-ECANCELED);
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}
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}
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nf_conntrack_get(reasm->nfct);
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skb->nfct = reasm->nfct;
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skb->nfctinfo = reasm->nfctinfo;
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return NF_ACCEPT;
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}
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return nf_conntrack_in(net, PF_INET6, hooknum, skb);
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}
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static unsigned int ipv6_conntrack_in(const struct nf_hook_ops *ops,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return __ipv6_conntrack_in(dev_net(in), ops->hooknum, skb, in, out,
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okfn);
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return nf_conntrack_in(dev_net(in), PF_INET6, ops->hooknum, skb);
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}
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static unsigned int ipv6_conntrack_local(const struct nf_hook_ops *ops,
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@ -240,8 +189,7 @@ static unsigned int ipv6_conntrack_local(const struct nf_hook_ops *ops,
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net_notice_ratelimited("ipv6_conntrack_local: packet too short\n");
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return NF_ACCEPT;
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}
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return __ipv6_conntrack_in(dev_net(out), ops->hooknum, skb, in, out,
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okfn);
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return nf_conntrack_in(dev_net(out), PF_INET6, ops->hooknum, skb);
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}
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static struct nf_hook_ops ipv6_conntrack_ops[] __read_mostly = {
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@ -633,31 +633,16 @@ ret_orig:
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return skb;
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}
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void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
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struct net_device *in, struct net_device *out,
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int (*okfn)(struct sk_buff *))
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void nf_ct_frag6_consume_orig(struct sk_buff *skb)
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{
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struct sk_buff *s, *s2;
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unsigned int ret = 0;
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for (s = NFCT_FRAG6_CB(skb)->orig; s;) {
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nf_conntrack_put_reasm(s->nfct_reasm);
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nf_conntrack_get_reasm(skb);
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s->nfct_reasm = skb;
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s2 = s->next;
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s->next = NULL;
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if (ret != -ECANCELED)
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ret = NF_HOOK_THRESH(NFPROTO_IPV6, hooknum, s,
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in, out, okfn,
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NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
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else
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kfree_skb(s);
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consume_skb(s);
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s = s2;
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}
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nf_conntrack_put_reasm(skb);
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}
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static int nf_ct_net_init(struct net *net)
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@ -75,8 +75,11 @@ static unsigned int ipv6_defrag(const struct nf_hook_ops *ops,
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if (reasm == skb)
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return NF_ACCEPT;
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nf_ct_frag6_output(ops->hooknum, reasm, (struct net_device *)in,
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(struct net_device *)out, okfn);
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nf_ct_frag6_consume_orig(reasm);
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NF_HOOK_THRESH(NFPROTO_IPV6, ops->hooknum, reasm,
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(struct net_device *) in, (struct net_device *) out,
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okfn, NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
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return NF_STOLEN;
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}
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@ -1139,12 +1139,6 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb, int af)
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ip_vs_fill_iph_skb(af, skb, &iph);
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#ifdef CONFIG_IP_VS_IPV6
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if (af == AF_INET6) {
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if (!iph.fragoffs && skb_nfct_reasm(skb)) {
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struct sk_buff *reasm = skb_nfct_reasm(skb);
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/* Save fw mark for coming frags */
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reasm->ipvs_property = 1;
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reasm->mark = skb->mark;
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}
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if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
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int related;
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int verdict = ip_vs_out_icmp_v6(skb, &related,
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@ -1614,12 +1608,6 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb, int af)
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#ifdef CONFIG_IP_VS_IPV6
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if (af == AF_INET6) {
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if (!iph.fragoffs && skb_nfct_reasm(skb)) {
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struct sk_buff *reasm = skb_nfct_reasm(skb);
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/* Save fw mark for coming frags. */
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reasm->ipvs_property = 1;
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reasm->mark = skb->mark;
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}
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if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
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int related;
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int verdict = ip_vs_in_icmp_v6(skb, &related, hooknum,
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@ -1671,9 +1659,8 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb, int af)
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/* sorry, all this trouble for a no-hit :) */
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IP_VS_DBG_PKT(12, af, pp, skb, 0,
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"ip_vs_in: packet continues traversal as normal");
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if (iph.fragoffs && !skb_nfct_reasm(skb)) {
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if (iph.fragoffs) {
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/* Fragment that couldn't be mapped to a conn entry
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* and don't have any pointer to a reasm skb
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* is missing module nf_defrag_ipv6
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*/
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IP_VS_DBG_RL("Unhandled frag, load nf_defrag_ipv6\n");
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@ -1755,38 +1742,6 @@ ip_vs_local_request4(const struct nf_hook_ops *ops, struct sk_buff *skb,
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#ifdef CONFIG_IP_VS_IPV6
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/*
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* AF_INET6 fragment handling
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* Copy info from first fragment, to the rest of them.
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*/
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static unsigned int
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ip_vs_preroute_frag6(const struct nf_hook_ops *ops, struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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struct sk_buff *reasm = skb_nfct_reasm(skb);
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struct net *net;
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/* Skip if not a "replay" from nf_ct_frag6_output or first fragment.
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* ipvs_property is set when checking first fragment
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* in ip_vs_in() and ip_vs_out().
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*/
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if (reasm)
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IP_VS_DBG(2, "Fragment recv prop:%d\n", reasm->ipvs_property);
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if (!reasm || !reasm->ipvs_property)
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return NF_ACCEPT;
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net = skb_net(skb);
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if (!net_ipvs(net)->enable)
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return NF_ACCEPT;
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/* Copy stored fw mark, saved in ip_vs_{in,out} */
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skb->mark = reasm->mark;
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return NF_ACCEPT;
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}
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/*
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* AF_INET6 handler in NF_INET_LOCAL_IN chain
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* Schedule and forward packets from remote clients
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@ -1924,14 +1879,6 @@ static struct nf_hook_ops ip_vs_ops[] __read_mostly = {
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.priority = 100,
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},
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#ifdef CONFIG_IP_VS_IPV6
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/* After mangle & nat fetch 2:nd fragment and following */
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{
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.hook = ip_vs_preroute_frag6,
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.owner = THIS_MODULE,
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.pf = NFPROTO_IPV6,
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.hooknum = NF_INET_PRE_ROUTING,
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.priority = NF_IP6_PRI_NAT_DST + 1,
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},
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/* After packet filtering, change source only for VS/NAT */
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{
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.hook = ip_vs_reply6,
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@ -65,7 +65,6 @@ static int get_callid(const char *dptr, unsigned int dataoff,
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static int
|
||||
ip_vs_sip_fill_param(struct ip_vs_conn_param *p, struct sk_buff *skb)
|
||||
{
|
||||
struct sk_buff *reasm = skb_nfct_reasm(skb);
|
||||
struct ip_vs_iphdr iph;
|
||||
unsigned int dataoff, datalen, matchoff, matchlen;
|
||||
const char *dptr;
|
||||
|
|
@ -79,15 +78,10 @@ ip_vs_sip_fill_param(struct ip_vs_conn_param *p, struct sk_buff *skb)
|
|||
/* todo: IPv6 fragments:
|
||||
* I think this only should be done for the first fragment. /HS
|
||||
*/
|
||||
if (reasm) {
|
||||
skb = reasm;
|
||||
dataoff = iph.thoff_reasm + sizeof(struct udphdr);
|
||||
} else
|
||||
dataoff = iph.len + sizeof(struct udphdr);
|
||||
dataoff = iph.len + sizeof(struct udphdr);
|
||||
|
||||
if (dataoff >= skb->len)
|
||||
return -EINVAL;
|
||||
/* todo: Check if this will mess-up the reasm skb !!! /HS */
|
||||
retc = skb_linearize(skb);
|
||||
if (retc < 0)
|
||||
return retc;
|
||||
|
|
|
|||
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Ссылка в новой задаче