[PATCH net-next 01/17] net/ipv6: Introduce payload_len helpers
From: Maxim Mikityanskiy <hidden>
Date: 2025-09-23 13:47:52
Subsystem:
cake qdisc, ethernet bridge, ipvs, netfilter, networking [general], networking [ipv4/ipv6], tc subsystem, the rest · Maintainers:
Toke Høiland-Jørgensen, Nikolay Aleksandrov, Ido Schimmel, Simon Horman, Julian Anastasov, Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds
From: Maxim Mikityanskiy <redacted> From: Maxim Mikityanskiy <redacted> The next commits will transition away from using the hop-by-hop extension header to encode packet length for BIG TCP. Add wrappers around ip6->payload_len that return the actual value if it's non-zero, and calculate it from skb->len if payload_len is set to zero (and a symmetrical setter). The new helpers are used wherever the surrounding code supports the hop-by-hop jumbo header for BIG TCP IPv6, or the corresponding IPv4 code uses skb_ip_totlen (e.g., in include/net/netfilter/nf_tables_ipv6.h). No behavioral change in this commit. Signed-off-by: Maxim Mikityanskiy <redacted> --- include/linux/ipv6.h | 20 ++++++++++++++++++++ include/net/ipv6.h | 2 -- include/net/netfilter/nf_tables_ipv6.h | 4 ++-- net/bridge/br_netfilter_ipv6.c | 2 +- net/bridge/netfilter/nf_conntrack_bridge.c | 4 ++-- net/ipv6/ip6_input.c | 2 +- net/ipv6/ip6_offload.c | 7 +++---- net/ipv6/output_core.c | 7 +------ net/netfilter/ipvs/ip_vs_xmit.c | 2 +- net/netfilter/nf_conntrack_ovs.c | 2 +- net/netfilter/nf_log_syslog.c | 2 +- net/sched/sch_cake.c | 2 +- 12 files changed, 34 insertions(+), 22 deletions(-)
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 43b7bb828738..44c4b791eceb 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h@@ -126,6 +126,26 @@ static inline unsigned int ipv6_transport_len(const struct sk_buff *skb) skb_network_header_len(skb); } +static inline unsigned int ipv6_payload_len(const struct sk_buff *skb, const struct ipv6hdr *ip6) +{ + u32 len = ntohs(ip6->payload_len); + + return (len || !skb_is_gso(skb) || !skb_is_gso_tcp(skb)) ? + len : skb->len - skb_network_offset(skb) - sizeof(struct ipv6hdr); +} + +static inline unsigned int skb_ipv6_payload_len(const struct sk_buff *skb) +{ + return ipv6_payload_len(skb, ipv6_hdr(skb)); +} + +#define IPV6_MAXPLEN 65535 + +static inline void ipv6_set_payload_len(struct ipv6hdr *ip6, unsigned int len) +{ + ip6->payload_len = len <= IPV6_MAXPLEN ? htons(len) : 0; +} + /* This structure contains results of exthdrs parsing as offsets from skb->nh.
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 2ccdf85f34f1..38b332f3028e 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h@@ -25,8 +25,6 @@ struct ip_tunnel_info; #define SIN6_LEN_RFC2133 24 -#define IPV6_MAXPLEN 65535 - /* * NextHeader field of IPv6 header */
diff --git a/include/net/netfilter/nf_tables_ipv6.h b/include/net/netfilter/nf_tables_ipv6.h
index a0633eeaec97..c53ac00bb974 100644
--- a/include/net/netfilter/nf_tables_ipv6.h
+++ b/include/net/netfilter/nf_tables_ipv6.h@@ -42,7 +42,7 @@ static inline int __nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt) if (ip6h->version != 6) return -1; - pkt_len = ntohs(ip6h->payload_len); + pkt_len = ipv6_payload_len(pkt->skb, ip6h); skb_len = pkt->skb->len - skb_network_offset(pkt->skb); if (pkt_len + sizeof(*ip6h) > skb_len) return -1;
@@ -86,7 +86,7 @@ static inline int nft_set_pktinfo_ipv6_ingress(struct nft_pktinfo *pkt) if (ip6h->version != 6) goto inhdr_error; - pkt_len = ntohs(ip6h->payload_len); + pkt_len = ipv6_payload_len(pkt->skb, ip6h); if (pkt_len + sizeof(*ip6h) > pkt->skb->len) { idev = __in6_dev_get(nft_in(pkt)); __IP6_INC_STATS(nft_net(pkt), idev, IPSTATS_MIB_INTRUNCATEDPKTS);
diff --git a/net/bridge/br_netfilter_ipv6.c b/net/bridge/br_netfilter_ipv6.c
index e0421eaa3abc..76ce70b4e7f3 100644
--- a/net/bridge/br_netfilter_ipv6.c
+++ b/net/bridge/br_netfilter_ipv6.c@@ -58,7 +58,7 @@ int br_validate_ipv6(struct net *net, struct sk_buff *skb) if (hdr->version != 6) goto inhdr_error; - pkt_len = ntohs(hdr->payload_len); + pkt_len = ipv6_payload_len(skb, hdr); if (hdr->nexthdr == NEXTHDR_HOP && nf_ip6_check_hbh_len(skb, &pkt_len)) goto drop;
diff --git a/net/bridge/netfilter/nf_conntrack_bridge.c b/net/bridge/netfilter/nf_conntrack_bridge.c
index 6482de4d8750..e3fd414906a0 100644
--- a/net/bridge/netfilter/nf_conntrack_bridge.c
+++ b/net/bridge/netfilter/nf_conntrack_bridge.c@@ -230,7 +230,7 @@ static int nf_ct_br_ipv6_check(const struct sk_buff *skb) if (hdr->version != 6) return -1; - len = ntohs(hdr->payload_len) + sizeof(struct ipv6hdr) + nhoff; + len = ipv6_payload_len(skb, hdr) + sizeof(struct ipv6hdr) + nhoff; if (skb->len < len) return -1;
@@ -270,7 +270,7 @@ static unsigned int nf_ct_bridge_pre(void *priv, struct sk_buff *skb, if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) return NF_ACCEPT; - len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len); + len = sizeof(struct ipv6hdr) + skb_ipv6_payload_len(skb); if (pskb_trim_rcsum(skb, len)) return NF_ACCEPT;
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 168ec07e31cc..2bcb981c91aa 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c@@ -262,7 +262,7 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev, skb->transport_header = skb->network_header + sizeof(*hdr); IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); - pkt_len = ntohs(hdr->payload_len); + pkt_len = ipv6_payload_len(skb, hdr); /* pkt_len may be zero if Jumbo payload option is present */ if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index fce91183797a..6762ce7909c8 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c@@ -372,12 +372,11 @@ INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff) hop_jumbo->jumbo_payload_len = htonl(payload_len + hoplen); iph->nexthdr = NEXTHDR_HOP; - iph->payload_len = 0; - } else { - iph = (struct ipv6hdr *)(skb->data + nhoff); - iph->payload_len = htons(payload_len); } + iph = (struct ipv6hdr *)(skb->data + nhoff); + ipv6_set_payload_len(iph, payload_len); + nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); if (WARN_ON(!ops || !ops->callbacks.gro_complete)) goto out;
diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c
index 1c9b283a4132..cba1684a3f30 100644
--- a/net/ipv6/output_core.c
+++ b/net/ipv6/output_core.c@@ -125,12 +125,7 @@ EXPORT_SYMBOL(ip6_dst_hoplimit); int __ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) { - int len; - - len = skb->len - sizeof(struct ipv6hdr); - if (len > IPV6_MAXPLEN) - len = 0; - ipv6_hdr(skb)->payload_len = htons(len); + ipv6_set_payload_len(ipv6_hdr(skb), skb->len - sizeof(struct ipv6hdr)); IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); /* if egress device is enslaved to an L3 master device pass the
diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index 95af252b2939..50501f3764f4 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c@@ -947,7 +947,7 @@ ip_vs_prepare_tunneled_skb(struct sk_buff *skb, int skb_af, *next_protocol = IPPROTO_IPV6; if (payload_len) *payload_len = - ntohs(old_ipv6h->payload_len) + + ipv6_payload_len(skb, old_ipv6h) + sizeof(*old_ipv6h); old_dsfield = ipv6_get_dsfield(old_ipv6h); *ttl = old_ipv6h->hop_limit;
diff --git a/net/netfilter/nf_conntrack_ovs.c b/net/netfilter/nf_conntrack_ovs.c
index 068e9489e1c2..a6988eeb1579 100644
--- a/net/netfilter/nf_conntrack_ovs.c
+++ b/net/netfilter/nf_conntrack_ovs.c@@ -121,7 +121,7 @@ int nf_ct_skb_network_trim(struct sk_buff *skb, int family) len = skb_ip_totlen(skb); break; case NFPROTO_IPV6: - len = ntohs(ipv6_hdr(skb)->payload_len); + len = skb_ipv6_payload_len(skb); if (ipv6_hdr(skb)->nexthdr == NEXTHDR_HOP) { int err = nf_ip6_check_hbh_len(skb, &len);
diff --git a/net/netfilter/nf_log_syslog.c b/net/netfilter/nf_log_syslog.c
index 86d5fc5d28e3..41503847d9d7 100644
--- a/net/netfilter/nf_log_syslog.c
+++ b/net/netfilter/nf_log_syslog.c@@ -561,7 +561,7 @@ dump_ipv6_packet(struct net *net, struct nf_log_buf *m, /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */ nf_log_buf_add(m, "LEN=%zu TC=%u HOPLIMIT=%u FLOWLBL=%u ", - ntohs(ih->payload_len) + sizeof(struct ipv6hdr), + ipv6_payload_len(skb, ih) + sizeof(struct ipv6hdr), (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20, ih->hop_limit, (ntohl(*(__be32 *)ih) & 0x000fffff));
diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c
index 32bacfc314c2..205f11c298ac 100644
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c@@ -1266,7 +1266,7 @@ static struct sk_buff *cake_ack_filter(struct cake_sched_data *q, ipv6_addr_cmp(&ipv6h_check->daddr, &ipv6h->daddr)) continue; - seglen = ntohs(ipv6h_check->payload_len); + seglen = ipv6_payload_len(skb, ipv6h_check); } else { WARN_ON(1); /* shouldn't happen */ continue;
--
2.50.1