treewide: Rename MAC address fields for clarity

c->mac isn't a great name, because it doesn't say whose mac address it is
and it's not necessarily obvious in all the contexts we use it.  Since this
is specifically the address that we (passt/pasta) use on the tap interface,
rename it to "our_tap_mac".  Rename the "mac_guest" field to "guest_mac"
to be grammatically consistent.

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

8 files changed, 28 insertions, 26 deletions

diff --git a/arp.c b/arp.c
index 93b22c5..53334da 100644
--- a/arp.c
+++ b/arp.c
@@ -72,7 +72,7 @@ int arp(const struct ctx *c, const struct pool *p)
 
 	ah->ar_op = htons(ARPOP_REPLY);
 	memcpy(am->tha,		am->sha,	sizeof(am->tha));
-	memcpy(am->sha,		c->mac,		sizeof(am->sha));
+	memcpy(am->sha,		c->our_tap_mac,	sizeof(am->sha));
 
 	memcpy(swap,		am->tip,	sizeof(am->tip));
 	memcpy(am->tip,		am->sip,	sizeof(am->tip));
@@ -80,7 +80,7 @@ int arp(const struct ctx *c, const struct pool *p)
 
 	l2len = sizeof(*eh) + sizeof(*ah) + sizeof(*am);
 	memcpy(eh->h_dest,	eh->h_source,	sizeof(eh->h_dest));
-	memcpy(eh->h_source,	c->mac,		sizeof(eh->h_source));
+	memcpy(eh->h_source,	c->our_tap_mac,	sizeof(eh->h_source));
 
 	tap_send_single(c, eh, l2len);
 
diff --git a/conf.c b/conf.c
index 830f91a..750fdc8 100644
--- a/conf.c
+++ b/conf.c
@@ -956,7 +956,7 @@ static void conf_print(const struct ctx *c)
 		info("Namespace interface: %s", c->pasta_ifn);
 
 	info("MAC:");
-	info("    host: %s", eth_ntop(c->mac, bufmac, sizeof(bufmac)));
+	info("    host: %s", eth_ntop(c->our_tap_mac, bufmac, sizeof(bufmac)));
 
 	if (c->ifi4) {
 		if (!c->no_dhcp) {
@@ -1289,7 +1289,7 @@ void conf(struct ctx *c, int argc, char **argv)
 			if (c->mode != MODE_PASTA)
 				die("--ns-mac-addr is for pasta mode only");
 
-			parse_mac(c->mac_guest, optarg);
+			parse_mac(c->guest_mac, optarg);
 			break;
 		case 5:
 			if (c->mode != MODE_PASTA)
@@ -1500,7 +1500,7 @@ void conf(struct ctx *c, int argc, char **argv)
 
 			break;
 		case 'M':
-			parse_mac(c->mac, optarg);
+			parse_mac(c->our_tap_mac, optarg);
 			break;
 		case 'g':
 			if (inet_pton(AF_INET6, optarg, &c->ip6.gw)     &&
@@ -1629,9 +1629,9 @@ void conf(struct ctx *c, int argc, char **argv)
 
 	nl_sock_init(c, false);
 	if (!v6_only)
-		c->ifi4 = conf_ip4(ifi4, &c->ip4, c->mac);
+		c->ifi4 = conf_ip4(ifi4, &c->ip4, c->our_tap_mac);
 	if (!v4_only)
-		c->ifi6 = conf_ip6(ifi6, &c->ip6, c->mac);
+		c->ifi6 = conf_ip6(ifi6, &c->ip6, c->our_tap_mac);
 	if ((!c->ifi4 && !c->ifi6) ||
 	    (*c->ip4.ifname_out && !c->ifi4) ||
 	    (*c->ip6.ifname_out && !c->ifi6))
diff --git a/dhcpv6.c b/dhcpv6.c
index 7dcca2a..bbed41d 100644
--- a/dhcpv6.c
+++ b/dhcpv6.c
@@ -574,8 +574,10 @@ void dhcpv6_init(const struct ctx *c)
 	resp.server_id.duid_time		= duid_time;
 	resp_not_on_link.server_id.duid_time	= duid_time;
 
-	memcpy(resp.server_id.duid_lladdr,		c->mac, sizeof(c->mac));
-	memcpy(resp_not_on_link.server_id.duid_lladdr,	c->mac, sizeof(c->mac));
+	memcpy(resp.server_id.duid_lladdr,
+	       c->our_tap_mac, sizeof(c->our_tap_mac));
+	memcpy(resp_not_on_link.server_id.duid_lladdr,
+	       c->our_tap_mac, sizeof(c->our_tap_mac));
 
 	resp.ia_addr.addr	= c->ip6.addr;
 }
diff --git a/ndp.c b/ndp.c
index 6dcb487..9c0fef4 100644
--- a/ndp.c
+++ b/ndp.c
@@ -247,7 +247,7 @@ int ndp(struct ctx *c, const struct icmp6hdr *ih, const struct in6_addr *saddr,
 
 		memcpy(&na.target_addr, &ns->target_addr,
 		       sizeof(na.target_addr));
-		memcpy(na.target_l2_addr.mac, c->mac, ETH_ALEN);
+		memcpy(na.target_l2_addr.mac, c->our_tap_mac, ETH_ALEN);
 
 	} else if (ih->icmp6_type == RS) {
 		size_t dns_s_len = 0;
@@ -331,7 +331,7 @@ int ndp(struct ctx *c, const struct icmp6hdr *ih, const struct in6_addr *saddr,
 		}
 
 dns_done:
-		memcpy(&ra.source_ll.mac, c->mac, ETH_ALEN);
+		memcpy(&ra.source_ll.mac, c->our_tap_mac, ETH_ALEN);
 	} else {
 		return 1;
 	}
diff --git a/passt.c b/passt.c
index 4b3c306..9637483 100644
--- a/passt.c
+++ b/passt.c
@@ -272,7 +272,7 @@ int main(int argc, char **argv)
 	if ((!c.no_udp && udp_init(&c)) || (!c.no_tcp && tcp_init(&c)))
 		exit(EXIT_FAILURE);
 
-	proto_update_l2_buf(c.mac_guest, c.mac);
+	proto_update_l2_buf(c.guest_mac, c.our_tap_mac);
 
 	if (c.ifi4 && !c.no_dhcp)
 		dhcp_init();
diff --git a/passt.h b/passt.h
index ef68403..fe3e47d 100644
--- a/passt.h
+++ b/passt.h
@@ -172,8 +172,8 @@ struct ip6_ctx {
  * @epollfd:		File descriptor for epoll instance
  * @fd_tap_listen:	File descriptor for listening AF_UNIX socket, if any
  * @fd_tap:		AF_UNIX socket, tuntap device, or pre-opened socket
- * @mac:		Host MAC address
- * @mac_guest:		MAC address of guest or namespace, seen or configured
+ * @our_tap_mac:	Pasta/passt's MAC on the tap link
+ * @guest_mac:		MAC address of guest or namespace, seen or configured
  * @hash_secret:	128-bit secret for siphash functions
  * @ifi4:		Index of template interface for IPv4, 0 if IPv4 disabled
  * @ip:			IPv4 configuration
@@ -226,8 +226,8 @@ struct ctx {
 	int epollfd;
 	int fd_tap_listen;
 	int fd_tap;
-	unsigned char mac[ETH_ALEN];
-	unsigned char mac_guest[ETH_ALEN];
+	unsigned char our_tap_mac[ETH_ALEN];
+	unsigned char guest_mac[ETH_ALEN];
 	uint64_t hash_secret[2];
 
 	unsigned int ifi4;
diff --git a/pasta.c b/pasta.c
index 1142f03..5f897d3 100644
--- a/pasta.c
+++ b/pasta.c
@@ -294,10 +294,10 @@ void pasta_ns_conf(struct ctx *c)
 		    strerror(-rc));
 
 	/* Get or set MAC in target namespace */
-	if (MAC_IS_ZERO(c->mac_guest))
-		nl_link_get_mac(nl_sock_ns, c->pasta_ifi, c->mac_guest);
+	if (MAC_IS_ZERO(c->guest_mac))
+		nl_link_get_mac(nl_sock_ns, c->pasta_ifi, c->guest_mac);
 	else
-		rc = nl_link_set_mac(nl_sock_ns, c->pasta_ifi, c->mac_guest);
+		rc = nl_link_set_mac(nl_sock_ns, c->pasta_ifi, c->guest_mac);
 	if (rc < 0)
 		die("Couldn't set MAC address in namespace: %s",
 		    strerror(-rc));
@@ -392,7 +392,7 @@ void pasta_ns_conf(struct ctx *c)
 		}
 	}
 
-	proto_update_l2_buf(c->mac_guest, NULL);
+	proto_update_l2_buf(c->guest_mac, NULL);
 }
 
 /**
diff --git a/tap.c b/tap.c
index 87be3a6..852d837 100644
--- a/tap.c
+++ b/tap.c
@@ -118,8 +118,8 @@ static void *tap_push_l2h(const struct ctx *c, void *buf, uint16_t proto)
 	struct ethhdr *eh = (struct ethhdr *)buf;
 
 	/* TODO: ARP table lookup */
-	memcpy(eh->h_dest, c->mac_guest, ETH_ALEN);
-	memcpy(eh->h_source, c->mac, ETH_ALEN);
+	memcpy(eh->h_dest, c->guest_mac, ETH_ALEN);
+	memcpy(eh->h_source, c->our_tap_mac, ETH_ALEN);
 	eh->h_proto = ntohs(proto);
 	return eh + 1;
 }
@@ -946,9 +946,9 @@ void tap_add_packet(struct ctx *c, ssize_t l2len, char *p)
 
 	eh = (struct ethhdr *)p;
 
-	if (memcmp(c->mac_guest, eh->h_source, ETH_ALEN)) {
-		memcpy(c->mac_guest, eh->h_source, ETH_ALEN);
-		proto_update_l2_buf(c->mac_guest, NULL);
+	if (memcmp(c->guest_mac, eh->h_source, ETH_ALEN)) {
+		memcpy(c->guest_mac, eh->h_source, ETH_ALEN);
+		proto_update_l2_buf(c->guest_mac, NULL);
 	}
 
 	switch (ntohs(eh->h_proto)) {
@@ -1337,6 +1337,6 @@ void tap_sock_init(struct ctx *c)
 		 * sends us packets.  Use the broadcast address so that our
 		 * first packets will reach it.
 		 */
-		memset(&c->mac_guest, 0xff, sizeof(c->mac_guest));
+		memset(&c->guest_mac, 0xff, sizeof(c->guest_mac));
 	}
 }