cc55bbef7
Denys Vlasenko
2020-12-12
Subject
traceroute: code shrink
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networking/traceroute.c+40 -30
| @@ -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; | |
| } | |