From 121d1e0941e05c64ee4223064dd83eb24e871739 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 30 Oct 2012 01:08:49 +0000 Subject: [PATCH] netfilter: ipv6: add getsockopt to retrieve origdst userspace can query the original ipv4 destination address of a REDIRECTed connection via getsockopt(m_sock, SOL_IP, SO_ORIGINAL_DST, &m_server_addr, &addrsize) but for ipv6 no such option existed. This adds getsockopt(..., IPPROTO_IPV6, IP6T_SO_ORIGINAL_DST, ...). Without this, userspace needs to parse /proc or use ctnetlink, which appears to be overkill. This uses option number 80 for IP6T_SO_ORIGINAL_DST, which is spare, to use the same number we use in the IPv4 socket option SO_ORIGINAL_DST. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/uapi/linux/in6.h | 1 + .../uapi/linux/netfilter_ipv6/ip6_tables.h | 3 + .../netfilter/nf_conntrack_l3proto_ipv6.c | 61 +++++++++++++++++++ 3 files changed, 65 insertions(+) diff --git a/include/uapi/linux/in6.h b/include/uapi/linux/in6.h index 1e3159989958..f79c3721da6e 100644 --- a/include/uapi/linux/in6.h +++ b/include/uapi/linux/in6.h @@ -240,6 +240,7 @@ struct in6_flowlabel_req { * * IP6T_SO_GET_REVISION_MATCH 68 * IP6T_SO_GET_REVISION_TARGET 69 + * IP6T_SO_ORIGINAL_DST 80 */ /* RFC5014: Source address selection */ diff --git a/include/uapi/linux/netfilter_ipv6/ip6_tables.h b/include/uapi/linux/netfilter_ipv6/ip6_tables.h index bf1ef65cc582..649c68062dca 100644 --- a/include/uapi/linux/netfilter_ipv6/ip6_tables.h +++ b/include/uapi/linux/netfilter_ipv6/ip6_tables.h @@ -178,6 +178,9 @@ struct ip6t_error { #define IP6T_SO_GET_REVISION_TARGET (IP6T_BASE_CTL + 5) #define IP6T_SO_GET_MAX IP6T_SO_GET_REVISION_TARGET +/* obtain original address if REDIRECT'd connection */ +#define IP6T_SO_ORIGINAL_DST 80 + /* ICMP matching stuff */ struct ip6t_icmp { __u8 type; /* type to match */ diff --git a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c index 8860d23e61cf..02dcafdc7a95 100644 --- a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c +++ b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c @@ -21,6 +21,7 @@ #include #include +#include #include #include #include @@ -295,6 +296,50 @@ static struct nf_hook_ops ipv6_conntrack_ops[] __read_mostly = { }, }; +static int +ipv6_getorigdst(struct sock *sk, int optval, void __user *user, int *len) +{ + const struct inet_sock *inet = inet_sk(sk); + const struct ipv6_pinfo *inet6 = inet6_sk(sk); + const struct nf_conntrack_tuple_hash *h; + struct sockaddr_in6 sin6; + struct nf_conntrack_tuple tuple = { .src.l3num = NFPROTO_IPV6 }; + struct nf_conn *ct; + + tuple.src.u3.in6 = inet6->rcv_saddr; + tuple.src.u.tcp.port = inet->inet_sport; + tuple.dst.u3.in6 = inet6->daddr; + tuple.dst.u.tcp.port = inet->inet_dport; + tuple.dst.protonum = sk->sk_protocol; + + if (sk->sk_protocol != IPPROTO_TCP && sk->sk_protocol != IPPROTO_SCTP) + return -ENOPROTOOPT; + + if (*len < 0 || (unsigned int) *len < sizeof(sin6)) + return -EINVAL; + + h = nf_conntrack_find_get(sock_net(sk), NF_CT_DEFAULT_ZONE, &tuple); + if (!h) { + pr_debug("IP6T_SO_ORIGINAL_DST: Can't find %pI6c/%u-%pI6c/%u.\n", + &tuple.src.u3.ip6, ntohs(tuple.src.u.tcp.port), + &tuple.dst.u3.ip6, ntohs(tuple.dst.u.tcp.port)); + return -ENOENT; + } + + ct = nf_ct_tuplehash_to_ctrack(h); + + sin6.sin6_family = AF_INET6; + sin6.sin6_port = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.tcp.port; + sin6.sin6_flowinfo = inet6->flow_label & IPV6_FLOWINFO_MASK; + memcpy(&sin6.sin6_addr, + &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.in6, + sizeof(sin6.sin6_addr)); + sin6.sin6_scope_id = sk->sk_bound_dev_if; + + nf_ct_put(ct); + return copy_to_user(user, &sin6, sizeof(sin6)) ? -EFAULT : 0; +} + #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) #include @@ -359,6 +404,14 @@ MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET6)); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Yasuyuki KOZAKAI @USAGI "); +static struct nf_sockopt_ops so_getorigdst6 = { + .pf = NFPROTO_IPV6, + .get_optmin = IP6T_SO_ORIGINAL_DST, + .get_optmax = IP6T_SO_ORIGINAL_DST + 1, + .get = ipv6_getorigdst, + .owner = THIS_MODULE, +}; + static int ipv6_net_init(struct net *net) { int ret = 0; @@ -425,6 +478,12 @@ static int __init nf_conntrack_l3proto_ipv6_init(void) need_conntrack(); nf_defrag_ipv6_enable(); + ret = nf_register_sockopt(&so_getorigdst6); + if (ret < 0) { + pr_err("Unable to register netfilter socket option\n"); + return ret; + } + ret = register_pernet_subsys(&ipv6_net_ops); if (ret < 0) goto cleanup_pernet; @@ -440,6 +499,7 @@ static int __init nf_conntrack_l3proto_ipv6_init(void) cleanup_ipv6: unregister_pernet_subsys(&ipv6_net_ops); cleanup_pernet: + nf_unregister_sockopt(&so_getorigdst6); return ret; } @@ -448,6 +508,7 @@ static void __exit nf_conntrack_l3proto_ipv6_fini(void) synchronize_net(); nf_unregister_hooks(ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops)); unregister_pernet_subsys(&ipv6_net_ops); + nf_unregister_sockopt(&so_getorigdst6); } module_init(nf_conntrack_l3proto_ipv6_init); -- 2.39.5