Re: [PATCH v5 net-next 03/14] netfilter: bridge: Add conntrack double vlan and pppoe
From: Nikolay Aleksandrov <razor@blackwall.org>
Date: 2025-02-06 14:20:59
Also in:
bridge, linux-mediatek, lkml, netdev, netfilter-devel
On 2/4/25 21:49, Eric Woudstra wrote:
quoted hunk ↗ jump to hunk
This adds the capability to conntrack 802.1ad, QinQ, PPPoE and PPPoE-in-Q packets that are passing a bridge. Signed-off-by: Eric Woudstra <redacted> --- net/bridge/netfilter/nf_conntrack_bridge.c | 81 ++++++++++++++++++---- 1 file changed, 69 insertions(+), 12 deletions(-)diff --git a/net/bridge/netfilter/nf_conntrack_bridge.c b/net/bridge/netfilter/nf_conntrack_bridge.c index 816bb0fde718..6411bfb53fad 100644 --- a/net/bridge/netfilter/nf_conntrack_bridge.c +++ b/net/bridge/netfilter/nf_conntrack_bridge.c@@ -242,53 +242,110 @@ 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 = (struct ppp_hdr *)(skb->data); + + offset = PPPOE_SES_HLEN; + if (!pskb_may_pull(skb, offset)) + return NF_ACCEPT;
You should reload ph because pskb_may_pull() may change the skb and it can become invalid
+ outer_proto = skb->protocol;
+ 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 = (struct vlan_hdr *)(skb->data);
+
+ offset = VLAN_HLEN;
+ if (!pskb_may_pull(skb, offset))
+ return NF_ACCEPT;ditto about vhdr, should be reloaded after the may pull
+ outer_proto = skb->protocol;
+ 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,