git: 3b0d328a2def - stable/13 - gif(4): Revert in{,6}_gif_output() misalignment handling

The branch stable/13 has been updated by marius:

URL: https://cgit.FreeBSD.org/src/commit/?id=3b0d328a2defb7a949f6ca5afd83281ceed1b6c8

commit 3b0d328a2defb7a949f6ca5afd83281ceed1b6c8
Author:     Marius Strobl <marius@FreeBSD.org>
AuthorDate: 2023-07-19 17:17:43 +0000
Commit:     Marius Strobl <marius@FreeBSD.org>
CommitDate: 2023-08-06 17:16:57 +0000

    gif(4): Revert in{,6}_gif_output() misalignment handling
    
    The code added in c89c8a1029860182eece5d51ec09119b9500e5a1 in order
    to compensate possible misalignment caused by prepending the IP4/6
    header with an EtherIP one got broken at some point by a rewrite of
    gif(4). For better or worse, 8018ac153f7671699ca008f31c0fad9caef2f531
    relaxed the alignment of struct ip from 32 bit to 16 bit, though. As
    a result, a 16 bit offset of the IPv4 header induced by the addition
    of the 16 bit EtherIP one no longer is a problem in the first place.
    The alignment of struct ip6_hdr currently is even only 8 bit, making
    it even less problematic with regards to possible misalignment.
    Thus, remove the code for handling misalignment in in{,6}_gif_output()
    altogether again.
    While at it, replace the 3 bcopy(9) calls in gif(4) with memcpy(9) as
    there's no need to handle overlap here.
    
    (cherry picked from commit e82d7b2952afaf9625a3d7b05d03c43c1d3e7d9c)
---
 sys/net/if_gif.c       |  2 +-
 sys/net/if_gif.h       |  2 --
 sys/netinet/in_gif.c   | 19 ++-----------------
 sys/netinet6/in6_gif.c | 19 ++-----------------
 4 files changed, 5 insertions(+), 37 deletions(-)

diff --git a/sys/net/if_gif.c b/sys/net/if_gif.c
index ea4b80690e50..4d2c1dcf091d 100644
--- a/sys/net/if_gif.c
+++ b/sys/net/if_gif.c
@@ -407,7 +407,7 @@ gif_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
 	uint32_t af;
 
 	if (dst->sa_family == AF_UNSPEC)
-		bcopy(dst->sa_data, &af, sizeof(af));
+		memcpy(&af, dst->sa_data, sizeof(af));
 	else
 		af = RO_GET_FAMILY(ro, dst);
 	/*
diff --git a/sys/net/if_gif.h b/sys/net/if_gif.h
index 2e61fcc166e1..f8fda6ddf801 100644
--- a/sys/net/if_gif.h
+++ b/sys/net/if_gif.h
@@ -94,8 +94,6 @@ struct etherip_header {
 } __packed;
 
 #define ETHERIP_VERSION			0x3
-/* mbuf adjust factor to force 32-bit alignment of IP header */
-#define	ETHERIP_ALIGN		2
 
 #define	GIF_WAIT()	epoch_wait_preempt(net_epoch_preempt)
 
diff --git a/sys/netinet/in_gif.c b/sys/netinet/in_gif.c
index a9f3d384fb5a..2caa9fcc23e2 100644
--- a/sys/netinet/in_gif.c
+++ b/sys/netinet/in_gif.c
@@ -272,31 +272,16 @@ in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
 {
 	struct gif_softc *sc = ifp->if_softc;
 	struct ip *ip;
-	int len;
 
 	/* prepend new IP header */
 	NET_EPOCH_ASSERT();
-	len = sizeof(struct ip);
-#ifndef __NO_STRICT_ALIGNMENT
-	if (proto == IPPROTO_ETHERIP)
-		len += ETHERIP_ALIGN;
-#endif
-	M_PREPEND(m, len, M_NOWAIT);
+	M_PREPEND(m, sizeof(struct ip), M_NOWAIT);
 	if (m == NULL)
 		return (ENOBUFS);
-#ifndef __NO_STRICT_ALIGNMENT
-	if (proto == IPPROTO_ETHERIP) {
-		len = mtod(m, vm_offset_t) & 3;
-		KASSERT(len == 0 || len == ETHERIP_ALIGN,
-		    ("in_gif_output: unexpected misalignment"));
-		m->m_data += len;
-		m->m_len -= ETHERIP_ALIGN;
-	}
-#endif
 	ip = mtod(m, struct ip *);
 
 	MPASS(sc->gif_family == AF_INET);
-	bcopy(sc->gif_iphdr, ip, sizeof(struct ip));
+	memcpy(ip, sc->gif_iphdr, sizeof(struct ip));
 	ip->ip_p = proto;
 	/* version will be set in ip_output() */
 	ip->ip_ttl = V_ip_gif_ttl;
diff --git a/sys/netinet6/in6_gif.c b/sys/netinet6/in6_gif.c
index 54cb81c6130f..eed311b86ff2 100644
--- a/sys/netinet6/in6_gif.c
+++ b/sys/netinet6/in6_gif.c
@@ -290,31 +290,16 @@ in6_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
 {
 	struct gif_softc *sc = ifp->if_softc;
 	struct ip6_hdr *ip6;
-	int len;
 
 	/* prepend new IP header */
 	NET_EPOCH_ASSERT();
-	len = sizeof(struct ip6_hdr);
-#ifndef __NO_STRICT_ALIGNMENT
-	if (proto == IPPROTO_ETHERIP)
-		len += ETHERIP_ALIGN;
-#endif
-	M_PREPEND(m, len, M_NOWAIT);
+	M_PREPEND(m, sizeof(struct ip6_hdr), M_NOWAIT);
 	if (m == NULL)
 		return (ENOBUFS);
-#ifndef __NO_STRICT_ALIGNMENT
-	if (proto == IPPROTO_ETHERIP) {
-		len = mtod(m, vm_offset_t) & 3;
-		KASSERT(len == 0 || len == ETHERIP_ALIGN,
-		    ("in6_gif_output: unexpected misalignment"));
-		m->m_data += len;
-		m->m_len -= ETHERIP_ALIGN;
-	}
-#endif
 
 	ip6 = mtod(m, struct ip6_hdr *);
 	MPASS(sc->gif_family == AF_INET6);
-	bcopy(sc->gif_ip6hdr, ip6, sizeof(struct ip6_hdr));
+	memcpy(ip6, sc->gif_ip6hdr, sizeof(struct ip6_hdr));
 
 	ip6->ip6_flow  |= htonl((uint32_t)ecn << 20);
 	ip6->ip6_nxt	= proto;