[PATCH v18 nf-next 3/4] netfilter: nft_set_pktinfo_ipv4/6_validate: Add nhoff argument
From: Eric Woudstra <hidden>
Date: 2026-02-22 19:59:06
Also in:
bridge, netfilter-devel
Subsystem:
netfilter, networking [general], the rest · Maintainers:
Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Add specifying an offset when calling nft_set_pktinfo_ipv4/6_validate() for cases where the ip(v6) header is not located at skb_network_header(). When an offset is specified other then zero, do not set pkt->tprot and the corresponding pkt->flags to not change rule processing. It does make the offsets in pktinfo available for code that is not checking pkt->flags to use the offsets, like nft_flow_offload_eval(). Existing behaviour for a rule like "tcp dport 22 accept" is not changed when, for instance, a PPPoE packet is being matched inside a bridge. Signed-off-by: Eric Woudstra <redacted> --- include/net/netfilter/nf_tables_ipv4.h | 21 +++++++++++++-------- include/net/netfilter/nf_tables_ipv6.h | 21 +++++++++++++-------- net/netfilter/nft_chain_filter.c | 8 ++++---- 3 files changed, 30 insertions(+), 20 deletions(-)
diff --git a/include/net/netfilter/nf_tables_ipv4.h b/include/net/netfilter/nf_tables_ipv4.h
index fcf967286e37..bd354937134f 100644
--- a/include/net/netfilter/nf_tables_ipv4.h
+++ b/include/net/netfilter/nf_tables_ipv4.h@@ -16,12 +16,12 @@ static inline void nft_set_pktinfo_ipv4(struct nft_pktinfo *pkt) pkt->fragoff = ntohs(ip->frag_off) & IP_OFFSET; } -static inline int __nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt) +static inline int __nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt, u32 nhoff) { struct iphdr *iph, _iph; u32 len, thoff, skb_len; - iph = skb_header_pointer(pkt->skb, skb_network_offset(pkt->skb), + iph = skb_header_pointer(pkt->skb, skb_network_offset(pkt->skb) + nhoff, sizeof(*iph), &_iph); if (!iph) return -1;
@@ -31,7 +31,7 @@ static inline int __nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt) len = iph_totlen(pkt->skb, iph); thoff = iph->ihl * 4; - skb_len = pkt->skb->len - skb_network_offset(pkt->skb); + skb_len = pkt->skb->len - skb_network_offset(pkt->skb) - nhoff; if (skb_len < len) return -1;
@@ -40,17 +40,22 @@ static inline int __nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt) else if (thoff < sizeof(*iph)) return -1; - pkt->flags = NFT_PKTINFO_L4PROTO; - pkt->tprot = iph->protocol; - pkt->thoff = skb_network_offset(pkt->skb) + thoff; + if (!nhoff) { + pkt->flags = NFT_PKTINFO_L4PROTO; + pkt->tprot = iph->protocol; + } else { + pkt->flags = 0; + pkt->tprot = 0; + } + pkt->thoff = skb_network_offset(pkt->skb) + nhoff + thoff; pkt->fragoff = ntohs(iph->frag_off) & IP_OFFSET; return 0; } -static inline void nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt) +static inline void nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt, u32 nhoff) { - if (__nft_set_pktinfo_ipv4_validate(pkt) < 0) + if (__nft_set_pktinfo_ipv4_validate(pkt, nhoff) < 0) nft_set_pktinfo_unspec(pkt); }
diff --git a/include/net/netfilter/nf_tables_ipv6.h b/include/net/netfilter/nf_tables_ipv6.h
index c53ac00bb974..1e84a891f268 100644
--- a/include/net/netfilter/nf_tables_ipv6.h
+++ b/include/net/netfilter/nf_tables_ipv6.h@@ -24,17 +24,17 @@ static inline void nft_set_pktinfo_ipv6(struct nft_pktinfo *pkt) pkt->fragoff = frag_off; } -static inline int __nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt) +static inline int __nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt, u32 nhoff) { #if IS_ENABLED(CONFIG_IPV6) unsigned int flags = IP6_FH_F_AUTH; struct ipv6hdr *ip6h, _ip6h; - unsigned int thoff = 0; + unsigned int thoff = nhoff; unsigned short frag_off; u32 pkt_len, skb_len; int protohdr; - ip6h = skb_header_pointer(pkt->skb, skb_network_offset(pkt->skb), + ip6h = skb_header_pointer(pkt->skb, skb_network_offset(pkt->skb) + nhoff, sizeof(*ip6h), &_ip6h); if (!ip6h) return -1;
@@ -43,7 +43,7 @@ static inline int __nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt) return -1; pkt_len = ipv6_payload_len(pkt->skb, ip6h); - skb_len = pkt->skb->len - skb_network_offset(pkt->skb); + skb_len = pkt->skb->len - skb_network_offset(pkt->skb) - nhoff; if (pkt_len + sizeof(*ip6h) > skb_len) return -1;
@@ -51,8 +51,13 @@ static inline int __nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt) if (protohdr < 0 || thoff > U16_MAX) return -1; - pkt->flags = NFT_PKTINFO_L4PROTO; - pkt->tprot = protohdr; + if (!nhoff) { + pkt->flags = NFT_PKTINFO_L4PROTO; + pkt->tprot = protohdr; + } else { + pkt->flags = 0; + pkt->tprot = 0; + } pkt->thoff = thoff; pkt->fragoff = frag_off;
@@ -62,9 +67,9 @@ static inline int __nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt) #endif } -static inline void nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt) +static inline void nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt, u32 nhoff) { - if (__nft_set_pktinfo_ipv6_validate(pkt) < 0) + if (__nft_set_pktinfo_ipv6_validate(pkt, nhoff) < 0) nft_set_pktinfo_unspec(pkt); }
diff --git a/net/netfilter/nft_chain_filter.c b/net/netfilter/nft_chain_filter.c
index b16185e9a6dd..d4d5eadaba9c 100644
--- a/net/netfilter/nft_chain_filter.c
+++ b/net/netfilter/nft_chain_filter.c@@ -238,10 +238,10 @@ nft_do_chain_bridge(void *priv, switch (eth_hdr(skb)->h_proto) { case htons(ETH_P_IP): - nft_set_pktinfo_ipv4_validate(&pkt); + nft_set_pktinfo_ipv4_validate(&pkt, 0); break; case htons(ETH_P_IPV6): - nft_set_pktinfo_ipv6_validate(&pkt); + nft_set_pktinfo_ipv6_validate(&pkt, 0); break; default: nft_set_pktinfo_unspec(&pkt);
@@ -293,10 +293,10 @@ static unsigned int nft_do_chain_netdev(void *priv, struct sk_buff *skb, switch (skb->protocol) { case htons(ETH_P_IP): - nft_set_pktinfo_ipv4_validate(&pkt); + nft_set_pktinfo_ipv4_validate(&pkt, 0); break; case htons(ETH_P_IPV6): - nft_set_pktinfo_ipv6_validate(&pkt); + nft_set_pktinfo_ipv6_validate(&pkt, 0); break; default: nft_set_pktinfo_unspec(&pkt);
--
2.53.0