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-rw-r--r--include/linux/in6.h3
-rw-r--r--include/linux/ipv6.h1
-rw-r--r--net/ipv6/ipv6_sockglue.c12
-rw-r--r--net/ipv6/tcp_ipv6.c14
4 files changed, 29 insertions, 1 deletions
diff --git a/include/linux/in6.h b/include/linux/in6.h
index bd55c6e..9b90cb2 100644
--- a/include/linux/in6.h
+++ b/include/linux/in6.h
@@ -265,6 +265,9 @@ struct in6_flowlabel_req {
#define IPV6_PREFER_SRC_CGA 0x0008
#define IPV6_PREFER_SRC_NONCGA 0x0800
+/* RFC5082: Generalized Ttl Security Mechanism */
+#define IPV6_MINHOPCOUNT 73
+
/*
* Multicast Routing:
* see include/linux/mroute6.h.
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index e0cc9a7..1bdbebf 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -348,6 +348,7 @@ struct ipv6_pinfo {
* 010: prefer public address
* 100: prefer care-of address
*/
+ __u8 min_hopcount;
__u8 tclass;
__u32 dst_cookie;
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 1160400..92295ad 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -767,6 +767,14 @@ pref_skip_coa:
break;
}
+ case IPV6_MINHOPCOUNT:
+ if (optlen < sizeof(int))
+ goto e_inval;
+ if (val < 0 || val > 255)
+ goto e_inval;
+ np->min_hopcount = val;
+ retv = 0;
+ break;
}
release_sock(sk);
@@ -1116,6 +1124,10 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
val |= IPV6_PREFER_SRC_HOME;
break;
+ case IPV6_MINHOPCOUNT:
+ val = np->min_hopcount;
+ break;
+
default:
return -ENOPROTOOPT;
}
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 1ababbb..6603511 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -353,6 +353,11 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
if (sk->sk_state == TCP_CLOSE)
goto out;
+ if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
+ NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
+ goto out;
+ }
+
tp = tcp_sk(sk);
seq = ntohl(th->seq);
if (sk->sk_state != TCP_LISTEN &&
@@ -1678,6 +1683,7 @@ ipv6_pktoptions:
static int tcp_v6_rcv(struct sk_buff *skb)
{
struct tcphdr *th;
+ struct ipv6hdr *hdr;
struct sock *sk;
int ret;
struct net *net = dev_net(skb->dev);
@@ -1704,12 +1710,13 @@ static int tcp_v6_rcv(struct sk_buff *skb)
goto bad_packet;
th = tcp_hdr(skb);
+ hdr = ipv6_hdr(skb);
TCP_SKB_CB(skb)->seq = ntohl(th->seq);
TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
skb->len - th->doff*4);
TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
TCP_SKB_CB(skb)->when = 0;
- TCP_SKB_CB(skb)->flags = ipv6_get_dsfield(ipv6_hdr(skb));
+ TCP_SKB_CB(skb)->flags = ipv6_get_dsfield(hdr);
TCP_SKB_CB(skb)->sacked = 0;
sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
@@ -1720,6 +1727,11 @@ process:
if (sk->sk_state == TCP_TIME_WAIT)
goto do_time_wait;
+ if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
+ NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
+ goto discard_and_relse;
+ }
+
if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
goto discard_and_relse;
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