[PATCH net-next 06/11] ip6_gre: add drop reasons to the RX path
From: Anton Danilov <hidden>
Date: 2026-08-31 21:52:01
Also in:
linux-kselftest, lkml
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
Mirror the previous patch on the IPv6 side: report SKB_DROP_REASON_GRE_TUNNEL_NOT_FOUND when no tunnel matches the packet, and tell that apart from a header that cannot be pulled (SKB_DROP_REASON_HDR_TRUNC) or a metadata allocation failure (SKB_DROP_REASON_NOMEM), which so far all ended up in the same plain kfree_skb() in gre_rcv(). ip6gre_rcv() and ip6erspan_rcv() get the same output parameter as their IPv4 counterparts. Assisted-by: Claude-Code:claude-opus-5 Signed-off-by: Anton Danilov <redacted> --- net/ipv6/ip6_gre.c | 36 ++++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 10 deletions(-)
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 736eefdb528f..27fbe175beec 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c@@ -454,7 +454,8 @@ static int ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt, return 0; } -static int ip6gre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi) +static int ip6gre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi, + enum skb_drop_reason *reason) { const struct ipv6hdr *ipv6h; struct ip6_tnl *tunnel;
@@ -473,8 +474,10 @@ static int ip6gre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi) tun_id = key32_to_tunnel_id(tpi->key); tun_dst = ipv6_tun_rx_dst(skb, flags, tun_id, 0); - if (!tun_dst) + if (!tun_dst) { + *reason = SKB_DROP_REASON_NOMEM; return PACKET_REJECT; + } ip6_tnl_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error); } else {
@@ -484,12 +487,14 @@ static int ip6gre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi) return PACKET_RCVD; } + *reason = SKB_DROP_REASON_GRE_TUNNEL_NOT_FOUND; return PACKET_REJECT; } static int ip6erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi, - int gre_hdr_len) + int gre_hdr_len, + enum skb_drop_reason *reason) { struct erspan_base_hdr *ershdr; const struct ipv6hdr *ipv6h;
@@ -497,8 +502,10 @@ static int ip6erspan_rcv(struct sk_buff *skb, struct ip6_tnl *tunnel; u8 ver; - if (unlikely(!pskb_may_pull(skb, sizeof(*ershdr)))) + if (unlikely(!pskb_may_pull(skb, sizeof(*ershdr)))) { + *reason = SKB_DROP_REASON_HDR_TRUNC; return PACKET_REJECT; + } ipv6h = ipv6_hdr(skb); ershdr = (struct erspan_base_hdr *)skb->data;
@@ -510,13 +517,17 @@ static int ip6erspan_rcv(struct sk_buff *skb, if (tunnel) { int len = erspan_hdr_len(ver); - if (unlikely(!pskb_may_pull(skb, len))) + if (unlikely(!pskb_may_pull(skb, len))) { + *reason = SKB_DROP_REASON_HDR_TRUNC; return PACKET_REJECT; + } if (__iptunnel_pull_header(skb, len, htons(ETH_P_TEB), - false, false) < 0) + false, false) < 0) { + *reason = SKB_DROP_REASON_HDR_TRUNC; return PACKET_REJECT; + } if (tunnel->parms.collect_md) { struct erspan_metadata *pkt_md, *md;
@@ -532,8 +543,10 @@ static int ip6erspan_rcv(struct sk_buff *skb, tun_dst = ipv6_tun_rx_dst(skb, flags, tun_id, sizeof(*md)); - if (!tun_dst) + if (!tun_dst) { + *reason = SKB_DROP_REASON_NOMEM; return PACKET_REJECT; + } /* MUST set options_len before referencing options */ info = &tun_dst->u.tun_info;
@@ -564,6 +577,7 @@ static int ip6erspan_rcv(struct sk_buff *skb, return PACKET_RCVD; } + *reason = SKB_DROP_REASON_GRE_TUNNEL_NOT_FOUND; return PACKET_REJECT; }
@@ -577,17 +591,19 @@ static int gre_rcv(struct sk_buff *skb) if (hdr_len < 0) goto drop; - if (iptunnel_pull_header(skb, hdr_len, tpi.proto, false)) + if (iptunnel_pull_header(skb, hdr_len, tpi.proto, false)) { + reason = SKB_DROP_REASON_HDR_TRUNC; goto drop; + } if (unlikely(tpi.proto == htons(ETH_P_ERSPAN) || tpi.proto == htons(ETH_P_ERSPAN2))) { - if (ip6erspan_rcv(skb, &tpi, hdr_len) == PACKET_RCVD) + if (ip6erspan_rcv(skb, &tpi, hdr_len, &reason) == PACKET_RCVD) return 0; goto out; } - if (ip6gre_rcv(skb, &tpi) == PACKET_RCVD) + if (ip6gre_rcv(skb, &tpi, &reason) == PACKET_RCVD) return 0; out:
--
2.47.3