git: 27cb3328173e - main - pf: micro-optimise padding check

The branch main has been updated by kp:

URL: https://cgit.FreeBSD.org/src/commit/?id=27cb3328173e4de80fad90c3b794b3eb0320d69a

commit 27cb3328173e4de80fad90c3b794b3eb0320d69a
Author:     Kristof Provost <kp@FreeBSD.org>
AuthorDate: 2025-02-14 15:23:53 +0000
Commit:     Kristof Provost <kp@FreeBSD.org>
CommitDate: 2025-02-21 09:16:52 +0000

    pf: micro-optimise padding check
    
    In most cases, IP fragments do not have an Ethernet padding.  So
    add a condition to save a useless call to m_adj() and have a paranoid
    length check in the other cases.
    OK henning@
    
    Obtained from:  OpenBSD, bluhm <bluhm@openbsd.org>, fcf0d61153
    Obtained from:  OpenBSD, chris <chris@openbsd.org>, ebe64b684c
    Sponsored by:   Rubicon Communications, LLC ("Netgate")
---
 sys/netpfil/pf/pf_norm.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sys/netpfil/pf/pf_norm.c b/sys/netpfil/pf/pf_norm.c
index ac74434cf2b7..98539be8c6ce 100644
--- a/sys/netpfil/pf/pf_norm.c
+++ b/sys/netpfil/pf/pf_norm.c
@@ -706,7 +706,8 @@ pf_join_fragment(struct pf_fragment *frag)
 	TAILQ_REMOVE(&frag->fr_queue, frent, fr_next);
 
 	m = frent->fe_m;
-	m_adj(m, (frent->fe_hdrlen + frent->fe_len) - m->m_pkthdr.len);
+	if ((frent->fe_hdrlen + frent->fe_len) < m->m_pkthdr.len)
+		m_adj(m, (frent->fe_hdrlen + frent->fe_len) - m->m_pkthdr.len);
 	uma_zfree(V_pf_frent_z, frent);
 	while ((frent = TAILQ_FIRST(&frag->fr_queue)) != NULL) {
 		TAILQ_REMOVE(&frag->fr_queue, frent, fr_next);
@@ -715,7 +716,8 @@ pf_join_fragment(struct pf_fragment *frag)
 		/* Strip off ip header. */
 		m_adj(m2, frent->fe_hdrlen);
 		/* Strip off any trailing bytes. */
-		m_adj(m2, frent->fe_len - m2->m_pkthdr.len);
+		if (frent->fe_len < m2->m_pkthdr.len)
+			m_adj(m2, frent->fe_len - m2->m_pkthdr.len);
 
 		uma_zfree(V_pf_frent_z, frent);
 		m_cat(m, m2);