From b8a51b38e4d4dec3e379d52c0fe1a66827f7cf1e Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Thu, 8 Nov 2018 12:19:23 +0100 Subject: fou, fou6: ICMP error handlers for FoU and GUE As the destination port in FoU and GUE receiving sockets doesn't necessarily match the remote destination port, we can't associate errors to the encapsulating tunnels with a socket lookup -- we need to blindly try them instead. This means we don't even know if we are handling errors for FoU or GUE without digging into the packets. Hence, implement a single handler for both, one for IPv4 and one for IPv6, that will check whether the packet that generated the ICMP error used a direct IP encapsulation or if it had a GUE header, and send the error to the matching protocol handler, if any. Signed-off-by: Stefano Brivio Reviewed-by: Sabrina Dubroca Signed-off-by: David S. Miller --- net/ipv4/fou.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) (limited to 'net/ipv4/fou.c') diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c index 500a59906b87..0d0ad19ecb87 100644 --- a/net/ipv4/fou.c +++ b/net/ipv4/fou.c @@ -3,6 +3,7 @@ #include #include #include +#include #include #include #include @@ -1003,15 +1004,82 @@ static int gue_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e, return 0; } +static int gue_err_proto_handler(int proto, struct sk_buff *skb, u32 info) +{ + const struct net_protocol *ipprot = rcu_dereference(inet_protos[proto]); + + if (ipprot && ipprot->err_handler) { + if (!ipprot->err_handler(skb, info)) + return 0; + } + + return -ENOENT; +} + +static int gue_err(struct sk_buff *skb, u32 info) +{ + int transport_offset = skb_transport_offset(skb); + struct guehdr *guehdr; + size_t optlen; + int ret; + + if (skb->len < sizeof(struct udphdr) + sizeof(struct guehdr)) + return -EINVAL; + + guehdr = (struct guehdr *)&udp_hdr(skb)[1]; + + switch (guehdr->version) { + case 0: /* Full GUE header present */ + break; + case 1: { + /* Direct encasulation of IPv4 or IPv6 */ + skb_set_transport_header(skb, -(int)sizeof(struct icmphdr)); + + switch (((struct iphdr *)guehdr)->version) { + case 4: + ret = gue_err_proto_handler(IPPROTO_IPIP, skb, info); + goto out; +#if IS_ENABLED(CONFIG_IPV6) + case 6: + ret = gue_err_proto_handler(IPPROTO_IPV6, skb, info); + goto out; +#endif + default: + ret = -EOPNOTSUPP; + goto out; + } + } + default: /* Undefined version */ + return -EOPNOTSUPP; + } + + if (guehdr->control) + return -ENOENT; + + optlen = guehdr->hlen << 2; + + if (validate_gue_flags(guehdr, optlen)) + return -EINVAL; + + skb_set_transport_header(skb, -(int)sizeof(struct icmphdr)); + ret = gue_err_proto_handler(guehdr->proto_ctype, skb, info); + +out: + skb_set_transport_header(skb, transport_offset); + return ret; +} + static const struct ip_tunnel_encap_ops fou_iptun_ops = { .encap_hlen = fou_encap_hlen, .build_header = fou_build_header, + .err_handler = gue_err, }; static const struct ip_tunnel_encap_ops gue_iptun_ops = { .encap_hlen = gue_encap_hlen, .build_header = gue_build_header, + .err_handler = gue_err, }; static int ip_tunnel_encap_add_fou_ops(void) -- cgit v1.2.3-59-g8ed1b