git: 4ad84614e490 - stable/14 - ip6_cksum.c: generalize in6_cksum_partial() to allow L2 headers in passed mbuf

The branch stable/14 has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=4ad84614e490cf2d59d670081b1ee1b065d89c15

commit 4ad84614e490cf2d59d670081b1ee1b065d89c15
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2025-02-19 12:38:34 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2025-03-20 03:13:36 +0000

    ip6_cksum.c: generalize in6_cksum_partial() to allow L2 headers in passed mbuf
    
    (cherry picked from commit fcf81de12f27d34a5c18168fd0c756c371a62076)
---
 sys/netinet6/in6.h       |  2 ++
 sys/netinet6/in6_cksum.c | 25 +++++++++++++++++--------
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/sys/netinet6/in6.h b/sys/netinet6/in6.h
index 0a4377638de1..b62da99f9293 100644
--- a/sys/netinet6/in6.h
+++ b/sys/netinet6/in6.h
@@ -666,6 +666,8 @@ struct ip6_hdr;
 
 int	in6_cksum(struct mbuf *, uint8_t, uint32_t, uint32_t);
 int	in6_cksum_partial(struct mbuf *, uint8_t, uint32_t, uint32_t, uint32_t);
+int	in6_cksum_partial_l2(struct mbuf *m, uint8_t nxt, uint32_t off_l3,
+	    uint32_t off_l4, uint32_t len, uint32_t cov);
 int	in6_cksum_pseudo(struct ip6_hdr *, uint32_t, uint8_t, uint16_t);
 
 int	in6_localaddr(struct in6_addr *);
diff --git a/sys/netinet6/in6_cksum.c b/sys/netinet6/in6_cksum.c
index cb2d89065f74..40d4d80ea4fb 100644
--- a/sys/netinet6/in6_cksum.c
+++ b/sys/netinet6/in6_cksum.c
@@ -250,14 +250,15 @@ in6_cksum_partial_one(void *_arg, void *data, u_int len)
 
 /*
  * m MUST contain a contiguous IP6 header.
- * off is an offset where TCP/UDP/ICMP6 header starts.
+ * off_l3 is an offset where ipv6 header starts.
+ * off_l4 is an offset where TCP/UDP/ICMP6 header starts.
  * len is a total length of a transport segment.
  * (e.g. TCP header + TCP payload)
  * cov is the number of bytes to be taken into account for the checksum
  */
 int
-in6_cksum_partial(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len,
-    uint32_t cov)
+in6_cksum_partial_l2(struct mbuf *m, uint8_t nxt, uint32_t off_l3,
+    uint32_t off_l4, uint32_t len, uint32_t cov)
 {
 	struct in6_cksum_partial_arg arg;
 	union l_util l_util;
@@ -275,9 +276,10 @@ in6_cksum_partial(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len,
 	} uph;
 
 	/* Sanity check. */
-	KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+"
-	    "len(%d)", __func__, m->m_pkthdr.len, off, len));
-	KASSERT(m->m_len >= sizeof(*ip6),
+	KASSERT(m->m_pkthdr.len >= off_l4 + len,
+	    ("%s: mbuf len (%d) < off(%d)+len(%d)",
+	    __func__, m->m_pkthdr.len, off_l4, len));
+	KASSERT(m->m_len >= off_l3 + sizeof(*ip6),
 	    ("%s: mbuf len %d < sizeof(ip6)", __func__, m->m_len));
 
 	/*
@@ -291,7 +293,7 @@ in6_cksum_partial(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len,
 	sum = uph.phs[0];  sum += uph.phs[1];
 	sum += uph.phs[2];  sum += uph.phs[3];
 
-	ip6 = mtod(m, struct ip6_hdr *);
+	ip6 = mtodo(m, off_l3);
 
 	/* IPv6 source address. */
 	scope = in6_getscope(&ip6->ip6_src);
@@ -315,7 +317,7 @@ in6_cksum_partial(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len,
 	 */
 	arg.sum = sum;
 	arg.rlen = 0;
-	(void)m_apply(m, off, cov, in6_cksum_partial_one, &arg);
+	(void)m_apply(m, off_l4, cov, in6_cksum_partial_one, &arg);
 	sum = arg.sum;
 
 	/*
@@ -330,6 +332,13 @@ in6_cksum_partial(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len,
 	return (~sum & 0xffff);
 }
 
+int
+in6_cksum_partial(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len,
+    uint32_t cov)
+{
+	return (in6_cksum_partial_l2(m, nxt, 0, off, len, cov));
+}
+
 int
 in6_cksum(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len)
 {