traceroute: make "ipv4 or ipv6?" cheaper to find out

function                                             old     new   delta
traceroute_init                                     1131    1135      +4
hexdump                                              274     270      -4
common_traceroute_main                              1730    1715     -15
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 4/-19)             Total: -15 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 21 insertions, 15 deletions

diff --git a/networking/traceroute.c b/networking/traceroute.c
index 8e13238bf..4d0ebc3b7 100644
--- a/networking/traceroute.c
+++ b/networking/traceroute.c
@@ -324,7 +324,6 @@
 #ifndef IPPROTO_IP
 # define IPPROTO_IP 0
 #endif
-
 /* Some operating systems, like GNU/Hurd, don't define SOL_RAW, but do have
  * IPPROTO_RAW. Since the IPPROTO definitions are also valid to use for
  * setsockopt (and take the same value as their corresponding SOL definitions,
@@ -391,19 +390,24 @@ struct globals {
         struct ip *outip;
         /* Pointer to ICMP or UDP payload (not header): */
         struct outdata_t *outdata;
-
         len_and_sockaddr *dest_lsa;
         len_and_sockaddr *from_lsa;     /* response came from this address */
         struct sockaddr *to;            /* response came to this (local) address */
-        int packlen;                    /* total length of packet */
-        int pmtu;                       /* Path MTU Discovery (RFC1191) */
         uint32_t ident;
         uint16_t port;                  /* start udp dest port # for probe packets */
+#if ENABLE_TRACEROUTE6
+        smallint ipv6;
+# define G_ipv6 G.ipv6
+#else
+# define G_ipv6 0
+#endif
+        int packlen;                    /* total length of packet */
+        int pmtu;                       /* Path MTU Discovery (RFC1191) */
         int waittime;                   /* time to wait for response (in seconds) */
         int first_ttl;
         int nprobes;
-        unsigned pausemsecs;
         int max_ttl;
+        unsigned pausemsecs;
         unsigned char recv_pkt[512];    /* last inbound (icmp) packet */
 };
 
@@ -482,7 +486,7 @@ send_probe(int seq, int ttl)
 
         /* Payload */
 #if ENABLE_TRACEROUTE6
-        if (dest_lsa->u.sa.sa_family == AF_INET6) {
+        if (G_ipv6) {
                 struct outdata6_t *pkt = (void *) outdata;
                 pkt->ident6 = ident;
                 pkt->seq6   = htonl(seq);
@@ -541,7 +545,7 @@ send_probe(int seq, int ttl)
 #endif
 
 #if ENABLE_TRACEROUTE6
-        if (dest_lsa->u.sa.sa_family == AF_INET6) {
+        if (G_ipv6) {
                 res = setsockopt_int(sndsock, SOL_IPV6, IPV6_UNICAST_HOPS, ttl);
                 if (res != 0)
                         bb_perror_msg_and_die("setsockopt(%s) %d", "UNICAST_HOPS", ttl);
@@ -585,7 +589,7 @@ pr_type(unsigned char t)
 [16]    = "Neighbor Advert", "Redirect",
         };
 
-        if (dest_lsa->u.sa.sa_family == AF_INET6) {
+        if (G_ipv6) {
                 if (t < 5)
                         return ttab6[t];
                 if (t < 128 || t > ND_REDIRECT)
@@ -772,7 +776,7 @@ packet6_ok(int read_len, int seq)
 static int
 packet_ok(int read_len, int seq)
 {
-        if (G.from_lsa->u.sa.sa_family == AF_INET)
+        if (!G_ipv6)
                 return packet4_ok(read_len, seq);
         return packet6_ok(read_len, seq);
 }
@@ -792,10 +796,10 @@ print(int read_len)
                 printf("  %s", ina);
         } else {
                 char *n = NULL;
-                if (G.from_lsa->u.sa.sa_family != AF_INET
+                if (G_ipv6
                  || G.from_lsa->u.sin.sin_addr.s_addr != INADDR_ANY
                 ) {
-                        /* Try to reverse resolve if it is not 0.0.0.0 */
+                        /* Reverse resolve if IPV6 or not 0.0.0.0 */
                         n = auto_string(xmalloc_sockaddr2host_noport(&G.from_lsa->u.sa));
                 }
                 printf("  %s (%s)", (n ? n : ina), ina);
@@ -808,7 +812,7 @@ print(int read_len)
                  * Reads from (AF_INET6, SOCK_RAW, IPPROTO_ICMPV6) do strip IPv6
                  * header and return only ICMP6 packet. Weird.
                  */
-                if (G.from_lsa->u.sa.sa_family == AF_INET6) {
+                if (G_ipv6) {
                         /* read_len -= sizeof(struct ip6_hdr); - WRONG! */
                 } else
 #endif
@@ -904,7 +908,9 @@ traceroute_init(int op, char **argv)
                 af = AF_INET6;
         dest_lsa = xhost_and_af2sockaddr(argv[0], port, af);
         af = dest_lsa->u.sa.sa_family;
+//TODO: make sure af == AF_INET[6]? (FEATURE_UNIX_LOCAL=y allows "local:/PATH" to be translated to AF_UNIX)
         if (af == AF_INET6) {
+                G_ipv6 = 1;
                 packlen = sizeof(struct ip6_hdr)
                                 + sizeof(struct udphdr)
                                 + sizeof(struct outdata6_t);
@@ -914,9 +920,9 @@ traceroute_init(int op, char **argv)
                                 + sizeof(struct outdata6_t);
         }
 #else
-        dest_lsa = xhost2sockaddr(argv[0], port);
+        /* accept only IPv4 addresses */
+        dest_lsa = xhost_and_af2sockaddr(argv[0], port, AF_INET);
 #endif
-//TODO: make sure af == AF_INET[6]? (FEATURE_UNIX_LOCAL=y allows "local:/PATH" to be translated to AF_UNIX)
         G.from_lsa = xmemdup(dest_lsa, LSA_LEN_SIZE + dest_lsa->len);
         G.to = xzalloc(dest_lsa->len);
         if (argv[1])
@@ -1117,7 +1123,7 @@ common_traceroute_main(int op, char **argv)
                                 memcpy(lastaddr, &G.from_lsa->u.sa, G.from_lsa->len);
                         }
                         print_delta_ms(t1, t2);
-                        if (G.from_lsa->u.sa.sa_family == AF_INET) {
+                        if (!G_ipv6) {
                                 if (op & OPT_TTL_FLAG) {
                                         struct ip *ip = (struct ip *)recv_pkt;
                                         printf(" (%d)", ip->ip_ttl);