treewide: Standardise variable names for various packet lengths

At various points we need to track the lengths of a packet including or
excluding various different sets of headers.  We don't always use the same
variable names for doing so.  Worse in some places we use the same name
for different things: e.g. tcp_fill_headers[46]() use ip_len for the
length including the IP headers, but then tcp_send_flag() which calls it
uses it to mean the IP payload length only.

To improve clarity, standardise on these names:
   dlen:		L4 protocol payload length ("data length")
   l4len:		plen + length of L4 protocol header
   l3len:		l4len + length of IPv4/IPv6 header
   l2len:		l3len + length of L2 (ethernet) header

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/icmp.c b/icmp.c
index 76bb9e9..1c5cf84 100644
--- a/icmp.c
+++ b/icmp.c
@@ -224,8 +224,8 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 	union sockaddr_inany sa = { .sa_family = af };
 	const socklen_t sl = af == AF_INET ? sizeof(sa.sa4) : sizeof(sa.sa6);
 	struct icmp_ping_flow *pingf, **id_sock;
+	size_t dlen, l4len;
 	uint16_t id, seq;
-	size_t plen;
 	void *pkt;
 
 	(void)saddr;
@@ -234,11 +234,11 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 	if (af == AF_INET) {
 		const struct icmphdr *ih;
 
-		if (!(pkt = packet_get(p, 0, 0, sizeof(*ih), &plen)))
+		if (!(pkt = packet_get(p, 0, 0, sizeof(*ih), &dlen)))
 			return 1;
 
 		ih =  (struct icmphdr *)pkt;
-		plen += sizeof(*ih);
+		l4len = dlen + sizeof(*ih);
 
 		if (ih->type != ICMP_ECHO)
 			return 1;
@@ -250,11 +250,11 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 	} else if (af == AF_INET6) {
 		const struct icmp6hdr *ih;
 
-		if (!(pkt = packet_get(p, 0, 0, sizeof(*ih), &plen)))
+		if (!(pkt = packet_get(p, 0, 0, sizeof(*ih), &dlen)))
 			return 1;
 
 		ih = (struct icmp6hdr *)pkt;
-		plen += sizeof(*ih);
+		l4len = dlen + sizeof(*ih);
 
 		if (ih->icmp6_type != ICMPV6_ECHO_REQUEST)
 			return 1;
@@ -274,7 +274,7 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 
 	pingf->ts = now->tv_sec;
 
-	if (sendto(pingf->sock, pkt, plen, MSG_NOSIGNAL, &sa.sa, sl) < 0) {
+	if (sendto(pingf->sock, pkt, l4len, MSG_NOSIGNAL, &sa.sa, sl) < 0) {
 		flow_dbg(pingf, "failed to relay request to socket: %s",
 			 strerror(errno));
 	} else {