[PATCH nf 1/4] netfilter: nf_log: remove dead ARPHRD_SIT handling from MAC/HW header logging

[Florian Westphal <fw@strlen.de>]

dump_mac_header() in nf_log_syslog.c and the HWHEADER dump in
nfnetlink_log.c special-case ARPHRD_SIT devices by backing the header
pointer up by ETH_HLEN before dumping dev->hard_header_len bytes, on
the assumption that a SIT tunnel's "hard header" covers the
underlying device's real Ethernet header plus the tunnel's IPv4
header.

That is no longer the case: ever sice commit 8ef9ba4d6666 ("IPv6: Set
SIT tunnel hard_header_len to zero"), dev->hard_header_len is 0 and
these branches are dead code.

No bug report in 6 years, so lets remove those branches.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nf_log_syslog.c | 23 +++--------------------
 net/netfilter/nfnetlink_log.c |  6 +-----
 2 files changed, 4 insertions(+), 25 deletions(-)

diff --git a/net/netfilter/nf_log_syslog.c b/net/netfilter/nf_log_syslog.c
index c3fd398ffcd7..3ff5a49a1c8d 100644
--- a/net/netfilter/nf_log_syslog.c
+++ b/net/netfilter/nf_log_syslog.c
@@ -820,26 +820,9 @@ static void dump_mac_header(struct nf_log_buf *m,
 		const unsigned char *p = skb_mac_header(skb);
 		unsigned int i;
 
-		if (dev->type == ARPHRD_SIT) {
-			p -= ETH_HLEN;
-
-			if (p < skb->head)
-				p = NULL;
-		}
-
-		if (p) {
-			nf_log_buf_add(m, "%02x", *p++);
-			for (i = 1; i < dev->hard_header_len; i++)
-				nf_log_buf_add(m, ":%02x", *p++);
-		}
-
-		if (dev->type == ARPHRD_SIT) {
-			const struct iphdr *iph =
-				(struct iphdr *)skb_mac_header(skb);
-
-			nf_log_buf_add(m, " TUNNEL=%pI4->%pI4", &iph->saddr,
-				       &iph->daddr);
-		}
+		nf_log_buf_add(m, "%02x", *p++);
+		for (i = 1; i < dev->hard_header_len; i++)
+			nf_log_buf_add(m, ":%02x", *p++);
 	}
 	nf_log_buf_add(m, " ");
 }
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index d923f2cb1398..0b590c117f4c 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -610,11 +610,7 @@ __build_packet_message(struct nfnl_log_net *log,
 
 		hwhdrp = skb_mac_header(skb);
 
-		if (skb->dev->type == ARPHRD_SIT)
-			hwhdrp -= ETH_HLEN;
-
-		if (hwhdrp >= skb->head &&
-		    nla_put(inst->skb, NFULA_HWHEADER,
+		if (nla_put(inst->skb, NFULA_HWHEADER,
 			    skb->dev->hard_header_len, hwhdrp))
 			goto nla_put_failure;
 	}
-- 
2.56.0