traceroute: code shrink

Move init code to a separate function.

function                                             old     new   delta
traceroute_init                                        -    1203   +1203
common_traceroute_main                              3391    2141   -1250
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/1 up/down: 1203/-1250)        Total: -47 bytes

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

1 files changed, 40 insertions, 30 deletions

diff --git a/networking/traceroute.c b/networking/traceroute.c
index 588570fcb..e6afdd8b9 100644
--- a/networking/traceroute.c
+++ b/networking/traceroute.c
@@ -394,8 +394,12 @@ struct globals {
         int packlen;                    /* total length of packet */
         int pmtu;                       /* Path MTU Discovery (RFC1191) */
         uint32_t ident;
-        uint16_t port; // 33434;        /* start udp dest port # for probe packets */
-        int waittime; // 5;             /* time to wait for response (in seconds) */
+        uint16_t port;                  /* start udp dest port # for probe packets */
+        int waittime;                   /* time to wait for response (in seconds) */
+        int first_ttl;
+        int nprobes;
+        unsigned pausemsecs;
+        int max_ttl;
         unsigned char recv_pkt[512];    /* last inbound (icmp) packet */
 };
 
@@ -412,8 +416,6 @@ struct globals {
 #define gwlist    (G.gwlist   )
 #define INIT_G() do { \
         SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
-        port = 33434; \
-        waittime = 5; \
 } while (0)
 
 #define outudp   ((struct udphdr *)(outip + 1))
@@ -862,22 +864,16 @@ print_delta_ms(unsigned t1p, unsigned t2p)
         printf("  %u.%03u ms", tt / 1000, tt % 1000);
 }
 
-/*
- * Usage: [-dFIlnrvx] [-g gateway] [-i iface] [-f first_ttl]
- * [-m max_ttl] [ -p port] [-q nqueries] [-s src_addr] [-t tos]
- * [-w waittime] [-z pausemsecs] host [packetlen]"
+/* Keeping init code in a separate (not inlined!) function
+ * for stack use reduction and better register allocation in main loop.
  */
-static int
-common_traceroute_main(int op, char **argv)
+static NOINLINE void
+traceroute_init(int op, char **argv)
 {
         int minpacket;
 #ifdef IP_TOS
         int tos = 0;
 #endif
-        int max_ttl = 30;
-        int nprobes = 3;
-        int first_ttl = 1;
-        unsigned pausemsecs = 0;
         char *source;
         char *device;
         char *tos_str;
@@ -893,14 +889,16 @@ common_traceroute_main(int op, char **argv)
 #else
         enum { af = AF_INET };
 #endif
-        int ttl;
-        int seq;
-        struct sockaddr *lastaddr;
 
         /* Ensure the socket fds won't be 0, 1 or 2 */
         bb_sanitize_stdio();
 
         INIT_G();
+        port = 33434;
+        waittime = 5;
+        G.first_ttl = 1;
+        G.nprobes = 3;
+        G.max_ttl = 30;
 
         op |= getopt32(argv, "^"
                 OPT_STRING
@@ -919,17 +917,17 @@ common_traceroute_main(int op, char **argv)
                 tos = xatou_range(tos_str, 0, 255);
 #endif
         if (op & OPT_MAX_TTL)
-                max_ttl = xatou_range(max_ttl_str, 1, 255);
+                G.max_ttl = xatou_range(max_ttl_str, 1, 255);
         if (op & OPT_PORT)
                 port = xatou16(port_str);
         if (op & OPT_NPROBES)
-                nprobes = xatou_range(nprobes_str, 1, INT_MAX);
+                G.nprobes = xatou_range(nprobes_str, 1, INT_MAX);
         if (op & OPT_WAITTIME)
                 waittime = xatou_range(waittime_str, 1, 24 * 60 * 60);
         if (op & OPT_PAUSE_MS)
-                pausemsecs = xatou_range(pausemsecs_str, 0, 60 * 60 * 1000);
+                G.pausemsecs = xatou_range(pausemsecs_str, 0, 60 * 60 * 1000);
         if (op & OPT_FIRST_TTL)
-                first_ttl = xatou_range(first_ttl_str, 1, max_ttl);
+                G.first_ttl = xatou_range(first_ttl_str, 1, G.max_ttl);
 
         /* Process destination and optional packet size */
         minpacket = sizeof(struct ip)
@@ -961,6 +959,9 @@ common_traceroute_main(int op, char **argv)
 #else
         dest_lsa = xhost2sockaddr(argv[0], port);
 #endif
+        G.from_lsa = xmemdup(dest_lsa, LSA_LEN_SIZE + dest_lsa->len);
+        G.to = xzalloc(dest_lsa->len);
+
         packlen = minpacket;
         if (argv[1])
                 packlen = xatoul_range(argv[1], minpacket, 32 * 1024);
@@ -1102,20 +1103,28 @@ common_traceroute_main(int op, char **argv)
 
         if (op & OPT_SOURCE)
                 printf(" from %s", source);
-        printf(", %d hops max, %d byte packets\n", max_ttl, packlen);
+        printf(", %d hops max, %d byte packets\n", G.max_ttl, packlen);
+}
+
+static int
+common_traceroute_main(int op, char **argv)
+{
+        int ttl;
+        int seq;
+        struct sockaddr *lastaddr;
+
+        traceroute_init(op, argv);
 
         lastaddr = xzalloc(dest_lsa->len);
-        G.from_lsa = xmemdup(dest_lsa, LSA_LEN_SIZE + dest_lsa->len);
-        G.to = xzalloc(dest_lsa->len);
         seq = 0;
-        for (ttl = first_ttl; ttl <= max_ttl; ++ttl) {
+        for (ttl = G.first_ttl; ttl <= G.max_ttl; ++ttl) {
                 int probe;
                 int unreachable = 0; /* counter */
                 int gotlastaddr = 0; /* flags */
                 int got_there = 0;
 
                 printf("%2d", ttl);
-                for (probe = 0; probe < nprobes; ++probe) {
+                for (probe = 0; probe < G.nprobes; ++probe) {
                         int read_len;
                         unsigned t1;
                         unsigned t2;
@@ -1123,14 +1132,15 @@ common_traceroute_main(int op, char **argv)
 
                         fflush_all();
                         if (probe != 0)
-                                msleep(pausemsecs);
+                                msleep(G.pausemsecs);
 
                         send_probe(++seq, ttl);
                         t2 = t1 = monotonic_us();
 
                         left_ms = waittime * 1000;
-                        /* NB: wait_for_reply() fills "G.from_lsa" and "G.to"
-                         * with "where it came from" and "to which local address it arrived".
+                        /* NB: wait_for_reply() fills "G.from_lsa" and "G.to" with
+                         * "where it came from" and "what local address it arrived to"
+                         * addresses.
                          */
                         while ((read_len = wait_for_reply(&t2, &left_ms)) != 0) {
                                 int icmp_code;
@@ -1255,7 +1265,7 @@ common_traceroute_main(int op, char **argv)
 
                 bb_putchar('\n');
                 if (got_there
-                 || (unreachable > 0 && unreachable >= nprobes - 1)
+                 || (unreachable > 0 && unreachable >= G.nprobes - 1)
                 ) {
                         break;
                 }