From 2fb39e6bbe3956bbd4a2ae0f14d68f6190945176 Mon Sep 17 00:00:00 2001 From: Zhenlei Huang Date: Sun, 9 Jun 2024 09:05:22 +0800 Subject: [PATCH] pfsync: Correctly check if bpf peers are present On creating the pfsync(4) interface, pfsync_clone_create() does an unconditional bpfattach(). Use bpf_peers_present() which was introduced in commit 16d878cc99ef [1] to check the presence of bpf peers. This will save a little CPU cycles and memory usage when the synchronisation interface is not configured and there is no bpf peers present. There should be no functional change. 1. 16d878cc99ef Fix the following bpf(4) race condition which can result in a panic Reviewed by: kp MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D45533 (cherry picked from commit 2671bde99295d9e01d10316d0f3fb8b6d21f0f4d) --- sys/netpfil/pf/if_pfsync.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/sys/netpfil/pf/if_pfsync.c b/sys/netpfil/pf/if_pfsync.c index 2cefe698b65..9aad44ccaf9 100644 --- a/sys/netpfil/pf/if_pfsync.c +++ b/sys/netpfil/pf/if_pfsync.c @@ -1792,7 +1792,7 @@ pfsync_sendout(int schedswi, int c) ("%s: sc_len %zu", __func__, b->b_len)); PFSYNC_BUCKET_LOCK_ASSERT(b); - if (ifp->if_bpf == NULL && sc->sc_sync_if == NULL) { + if (!bpf_peers_present(ifp->if_bpf) && sc->sc_sync_if == NULL) { pfsync_drop(sc); return; } @@ -1921,10 +1921,10 @@ pfsync_sendout(int schedswi, int c) V_pfsyncstats.pfsyncs_oacts[PFSYNC_ACT_EOF]++; /* we're done, let's put it on the wire */ - if (ifp->if_bpf) { + if (bpf_peers_present(ifp->if_bpf)) { m->m_data += aflen; m->m_len = m->m_pkthdr.len = len - aflen; - BPF_MTAP(ifp, m); + bpf_mtap(ifp->if_bpf, m); m->m_data -= aflen; m->m_len = m->m_pkthdr.len = len; }