[PATCH v11 nf-next 1/2] netfilter: bridge: Add conntrack double vlan and pppoe

[Eric Woudstra]

This adds the capability to conntrack 802.1ad, QinQ, PPPoE and PPPoE-in-Q
packets that are passing a bridge.

Reviewed-by: Nikolay Aleksandrov <ra...@blackwall.org>
Signed-off-by: Eric Woudstra <ericwo...@gmail.com>
---
 net/bridge/netfilter/nf_conntrack_bridge.c | 83 ++++++++++++++++++----
 1 file changed, 71 insertions(+), 12 deletions(-)

diff --git a/net/bridge/netfilter/nf_conntrack_bridge.c 
b/net/bridge/netfilter/nf_conntrack_bridge.c
index 816bb0fde718..4b4e3751fb13 100644
--- a/net/bridge/netfilter/nf_conntrack_bridge.c
+++ b/net/bridge/netfilter/nf_conntrack_bridge.c
@@ -242,53 +242,112 @@ static unsigned int nf_ct_bridge_pre(void *priv, struct 
sk_buff *skb,
 {
        struct nf_hook_state bridge_state = *state;
        enum ip_conntrack_info ctinfo;
+       int ret, offset = 0;
        struct nf_conn *ct;
-       u32 len;
-       int ret;
+       __be16 outer_proto;
+       u32 len, data_len;
 
        ct = nf_ct_get(skb, &ctinfo);
        if ((ct && !nf_ct_is_template(ct)) ||
            ctinfo == IP_CT_UNTRACKED)
                return NF_ACCEPT;
 
+       switch (skb->protocol) {
+       case htons(ETH_P_PPP_SES): {
+               struct ppp_hdr {
+                       struct pppoe_hdr hdr;
+                       __be16 proto;
+               } *ph;
+
+               offset = PPPOE_SES_HLEN;
+               if (!pskb_may_pull(skb, offset))
+                       return NF_ACCEPT;
+               outer_proto = skb->protocol;
+               ph = (struct ppp_hdr *)(skb->data);
+               switch (ph->proto) {
+               case htons(PPP_IP):
+                       skb->protocol = htons(ETH_P_IP);
+                       break;
+               case htons(PPP_IPV6):
+                       skb->protocol = htons(ETH_P_IPV6);
+                       break;
+               default:
+                       nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
+                       return NF_ACCEPT;
+               }
+               data_len = ntohs(ph->hdr.length) - 2;
+               skb_pull_rcsum(skb, offset);
+               skb_reset_network_header(skb);
+               break;
+       }
+       case htons(ETH_P_8021Q): {
+               struct vlan_hdr *vhdr;
+
+               offset = VLAN_HLEN;
+               if (!pskb_may_pull(skb, offset))
+                       return NF_ACCEPT;
+               outer_proto = skb->protocol;
+               vhdr = (struct vlan_hdr *)(skb->data);
+               skb->protocol = vhdr->h_vlan_encapsulated_proto;
+               data_len = U32_MAX;
+               skb_pull_rcsum(skb, offset);
+               skb_reset_network_header(skb);
+               break;
+       }
+       default:
+               data_len = U32_MAX;
+               break;
+       }
+
+       ret = NF_ACCEPT;
        switch (skb->protocol) {
        case htons(ETH_P_IP):
                if (!pskb_may_pull(skb, sizeof(struct iphdr)))
-                       return NF_ACCEPT;
+                       goto do_not_track;
 
                len = skb_ip_totlen(skb);
+               if (data_len < len)
+                       len = data_len;
                if (pskb_trim_rcsum(skb, len))
-                       return NF_ACCEPT;
+                       goto do_not_track;
 
                if (nf_ct_br_ip_check(skb))
-                       return NF_ACCEPT;
+                       goto do_not_track;
 
                bridge_state.pf = NFPROTO_IPV4;
                ret = nf_ct_br_defrag4(skb, &bridge_state);
                break;
        case htons(ETH_P_IPV6):
                if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
-                       return NF_ACCEPT;
+                       goto do_not_track;
 
                len = sizeof(struct ipv6hdr) + 
ntohs(ipv6_hdr(skb)->payload_len);
+               if (data_len < len)
+                       len = data_len;
                if (pskb_trim_rcsum(skb, len))
-                       return NF_ACCEPT;
+                       goto do_not_track;
 
                if (nf_ct_br_ipv6_check(skb))
-                       return NF_ACCEPT;
+                       goto do_not_track;
 
                bridge_state.pf = NFPROTO_IPV6;
                ret = nf_ct_br_defrag6(skb, &bridge_state);
                break;
        default:
                nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
-               return NF_ACCEPT;
+               goto do_not_track;
        }
 
-       if (ret != NF_ACCEPT)
-               return ret;
+       if (ret == NF_ACCEPT)
+               ret = nf_conntrack_in(skb, &bridge_state);
 
-       return nf_conntrack_in(skb, &bridge_state);
+do_not_track:
+       if (offset) {
+               skb_push_rcsum(skb, offset);
+               skb_reset_network_header(skb);
+               skb->protocol = outer_proto;
+       }
+       return ret;
 }
 
 static unsigned int nf_ct_bridge_in(void *priv, struct sk_buff *skb,
-- 
2.47.1