diff mbox series

[net-next,3/5] net: dropreason: add SKB_DROP_REASON_DUP_FRAG

Message ID 20221028133043.2312984-4-edumazet@google.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series inet: add drop monitor support | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5329 this patch: 5329
netdev/cc_maintainers warning 7 maintainers not CCed: dsahern@kernel.org pablo@netfilter.org netfilter-devel@vger.kernel.org fw@strlen.de yoshfuji@linux-ipv6.org coreteam@netfilter.org kadlec@netfilter.org
netdev/build_clang success Errors and warnings before: 1119 this patch: 1119
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 5511 this patch: 5511
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 91 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Oct. 28, 2022, 1:30 p.m. UTC 
This is used to track when a duplicate segment received by various
reassembly units is dropped.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/dropreason.h                |  3 +++
 net/ipv4/ip_fragment.c                  | 13 +++++++++----
 net/ipv6/netfilter/nf_conntrack_reasm.c |  2 +-
 net/ipv6/reassembly.c                   | 13 +++++++++----
 4 files changed, 22 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/include/net/dropreason.h b/include/net/dropreason.h
index 0bd18c14dae0a570a150c31eeea99fe85bc734b0..602d555a5f8392715ec03f85418ecb98926d0481 100644
--- a/include/net/dropreason.h
+++ b/include/net/dropreason.h
@@ -68,6 +68,7 @@ 
 	FN(IP_INADDRERRORS)		\
 	FN(IP_INNOROUTES)		\
 	FN(PKT_TOO_BIG)			\
+	FN(DUP_FRAG)			\
 	FNe(MAX)
 
 /**
@@ -300,6 +301,8 @@  enum skb_drop_reason {
 	 * MTU)
 	 */
 	SKB_DROP_REASON_PKT_TOO_BIG,
+	/** @SKB_DROP_REASON_DUP_FRAG: duplicate fragment */
+	SKB_DROP_REASON_DUP_FRAG,
 	/**
 	 * @SKB_DROP_REASON_MAX: the maximum of drop reason, which shouldn't be
 	 * used as a real 'reason'
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index fb153569889ecc8541640674880ff03e8c7bf24f..676bd8d259555448457dfd98ce4316c4b549a30a 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -278,10 +278,14 @@  static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 	struct net_device *dev;
 	unsigned int fragsize;
 	int err = -ENOENT;
+	SKB_DR(reason);
 	u8 ecn;
 
-	if (qp->q.flags & INET_FRAG_COMPLETE)
+	/* If reassembly is already done, @skb must be a duplicate frag. */
+	if (qp->q.flags & INET_FRAG_COMPLETE) {
+		SKB_DR_SET(reason, DUP_FRAG);
 		goto err;
+	}
 
 	if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
 	    unlikely(ip_frag_too_far(qp)) &&
@@ -382,8 +386,9 @@  static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 
 insert_error:
 	if (err == IPFRAG_DUP) {
-		kfree_skb(skb);
-		return -EINVAL;
+		SKB_DR_SET(reason, DUP_FRAG);
+		err = -EINVAL;
+		goto err;
 	}
 	err = -EINVAL;
 	__IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS);
@@ -391,7 +396,7 @@  static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 	inet_frag_kill(&qp->q);
 	__IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
 err:
-	kfree_skb(skb);
+	kfree_skb_reason(skb, reason);
 	return err;
 }
 
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index 38db0064d6613a8472ec2835afdbf80071c1fcc2..d13240f13607bae8833d4e53471c575280ff49dc 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -253,7 +253,7 @@  static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb,
 	if (err) {
 		if (err == IPFRAG_DUP) {
 			/* No error for duplicates, pretend they got queued. */
-			kfree_skb(skb);
+			kfree_skb_reason(skb, SKB_DROP_REASON_DUP_FRAG);
 			return -EINPROGRESS;
 		}
 		goto insert_error;
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index ff866f2a879e00769b273c22b970740eaebb6d99..5bc8a28e67f944c9e7bead79afa8b80a34b92db9 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -112,10 +112,14 @@  static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 	struct sk_buff *prev_tail;
 	struct net_device *dev;
 	int err = -ENOENT;
+	SKB_DR(reason);
 	u8 ecn;
 
-	if (fq->q.flags & INET_FRAG_COMPLETE)
+	/* If reassembly is already done, @skb must be a duplicate frag. */
+	if (fq->q.flags & INET_FRAG_COMPLETE) {
+		SKB_DR_SET(reason, DUP_FRAG);
 		goto err;
+	}
 
 	err = -EINVAL;
 	offset = ntohs(fhdr->frag_off) & ~0x7;
@@ -226,8 +230,9 @@  static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 
 insert_error:
 	if (err == IPFRAG_DUP) {
-		kfree_skb(skb);
-		return -EINVAL;
+		SKB_DR_SET(reason, DUP_FRAG);
+		err = -EINVAL;
+		goto err;
 	}
 	err = -EINVAL;
 	__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
@@ -237,7 +242,7 @@  static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 	__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 			IPSTATS_MIB_REASMFAILS);
 err:
-	kfree_skb(skb);
+	kfree_skb_reason(skb, reason);
 	return err;
 }