From: Jason A. Donenfeld Jason@zx2c4.com
commit 0b41713b606694257b90d61ba7e2712d8457648b upstream.
This introduces a helper function to be called only by network drivers that wraps calls to icmp[v6]_send in a conntrack transformation, in case NAT has been used. We don't want to pollute the non-driver path, though, so we introduce this as a helper to be called by places that actually make use of this, as suggested by Florian.
Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Cc: Florian Westphal fw@strlen.de Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/icmpv6.h | 6 ++++++ include/net/icmp.h | 6 ++++++ net/ipv4/icmp.c | 33 +++++++++++++++++++++++++++++++++ net/ipv6/ip6_icmp.c | 34 ++++++++++++++++++++++++++++++++++ 4 files changed, 79 insertions(+)
--- a/include/linux/icmpv6.h +++ b/include/linux/icmpv6.h @@ -31,6 +31,12 @@ static inline void icmpv6_send(struct sk } #endif
+#if IS_ENABLED(CONFIG_NF_NAT) +void icmpv6_ndo_send(struct sk_buff *skb_in, u8 type, u8 code, __u32 info); +#else +#define icmpv6_ndo_send icmpv6_send +#endif + extern int icmpv6_init(void); extern int icmpv6_err_convert(u8 type, u8 code, int *err); --- a/include/net/icmp.h +++ b/include/net/icmp.h @@ -47,6 +47,12 @@ static inline void icmp_send(struct sk_b __icmp_send(skb_in, type, code, info, &IPCB(skb_in)->opt); }
+#if IS_ENABLED(CONFIG_NF_NAT) +void icmp_ndo_send(struct sk_buff *skb_in, int type, int code, __be32 info); +#else +#define icmp_ndo_send icmp_send +#endif + int icmp_rcv(struct sk_buff *skb); void icmp_err(struct sk_buff *skb, u32 info); int icmp_init(void); --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -754,6 +754,39 @@ out:; } EXPORT_SYMBOL(__icmp_send);
+#if IS_ENABLED(CONFIG_NF_NAT) +#include <net/netfilter/nf_conntrack.h> +void icmp_ndo_send(struct sk_buff *skb_in, int type, int code, __be32 info) +{ + struct sk_buff *cloned_skb = NULL; + enum ip_conntrack_info ctinfo; + struct nf_conn *ct; + __be32 orig_ip; + + ct = nf_ct_get(skb_in, &ctinfo); + if (!ct || !(ct->status & IPS_SRC_NAT)) { + icmp_send(skb_in, type, code, info); + return; + } + + if (skb_shared(skb_in)) + skb_in = cloned_skb = skb_clone(skb_in, GFP_ATOMIC); + + if (unlikely(!skb_in || skb_network_header(skb_in) < skb_in->head || + (skb_network_header(skb_in) + sizeof(struct iphdr)) > + skb_tail_pointer(skb_in) || skb_ensure_writable(skb_in, + skb_network_offset(skb_in) + sizeof(struct iphdr)))) + goto out; + + orig_ip = ip_hdr(skb_in)->saddr; + ip_hdr(skb_in)->saddr = ct->tuplehash[0].tuple.src.u3.ip; + icmp_send(skb_in, type, code, info); + ip_hdr(skb_in)->saddr = orig_ip; +out: + consume_skb(cloned_skb); +} +EXPORT_SYMBOL(icmp_ndo_send); +#endif
static void icmp_socket_deliver(struct sk_buff *skb, u32 info) { --- a/net/ipv6/ip6_icmp.c +++ b/net/ipv6/ip6_icmp.c @@ -45,4 +45,38 @@ out: rcu_read_unlock(); } EXPORT_SYMBOL(icmpv6_send); + +#if IS_ENABLED(CONFIG_NF_NAT) +#include <net/netfilter/nf_conntrack.h> +void icmpv6_ndo_send(struct sk_buff *skb_in, u8 type, u8 code, __u32 info) +{ + struct sk_buff *cloned_skb = NULL; + enum ip_conntrack_info ctinfo; + struct in6_addr orig_ip; + struct nf_conn *ct; + + ct = nf_ct_get(skb_in, &ctinfo); + if (!ct || !(ct->status & IPS_SRC_NAT)) { + icmpv6_send(skb_in, type, code, info); + return; + } + + if (skb_shared(skb_in)) + skb_in = cloned_skb = skb_clone(skb_in, GFP_ATOMIC); + + if (unlikely(!skb_in || skb_network_header(skb_in) < skb_in->head || + (skb_network_header(skb_in) + sizeof(struct ipv6hdr)) > + skb_tail_pointer(skb_in) || skb_ensure_writable(skb_in, + skb_network_offset(skb_in) + sizeof(struct ipv6hdr)))) + goto out; + + orig_ip = ipv6_hdr(skb_in)->saddr; + ipv6_hdr(skb_in)->saddr = ct->tuplehash[0].tuple.src.u3.in6; + icmpv6_send(skb_in, type, code, info); + ipv6_hdr(skb_in)->saddr = orig_ip; +out: + consume_skb(cloned_skb); +} +EXPORT_SYMBOL(icmpv6_ndo_send); +#endif #endif