ref: dc96f164a2b72ccb209ae98ce50a11087cbe44f8
dir: /sys/src/cmd/ip/traceroute.c/
#include <u.h> #include <libc.h> #include <ctype.h> #include <bio.h> #include <ndb.h> #include <ip.h> #include "icmp.h" enum{ Maxstring= 128, Maxpath= 256, }; typedef struct DS DS; struct DS { /* dial string */ char buf[Maxstring]; char *netdir; char *proto; char *rem; }; char *argv0; int debug; void histogram(long *t, int n, int buckets, long lo, long hi); void usage(void) { fprint(2, "usage: %s [-n][-a tries][-h buckets][-t ttl][-x net] [protocol!]destination\n", argv0); exits("usage"); } static int csquery(DS *ds, char *clone, char *dest) { int n, fd; char *p, buf[Maxstring]; /* * open connection server */ snprint(buf, sizeof(buf), "%s/cs", ds->netdir); fd = open(buf, ORDWR); if(fd < 0){ if(!isdigit(*dest)){ werrstr("can't translate"); return -1; } /* no connection server, don't translate */ snprint(clone, sizeof(clone), "%s/%s/clone", ds->netdir, ds->proto); strcpy(dest, ds->rem); return 0; } /* * ask connection server to translate */ sprint(buf, "%s!%s", ds->proto, ds->rem); if(write(fd, buf, strlen(buf)) < 0){ close(fd); return -1; } /* * get an address. */ seek(fd, 0, 0); n = read(fd, buf, sizeof(buf) - 1); close(fd); if(n <= 0){ werrstr("problem with cs"); return -1; } buf[n] = 0; p = strchr(buf, ' '); if(p == 0){ werrstr("problem with cs"); return -1; } *p++ = 0; strcpy(clone, buf); strcpy(dest, p); return 0; } /* * call the dns process and have it try to resolve the mx request */ static int dodnsquery(DS *ds, char *ip, char *dom) { char *p; Ndbtuple *t, *nt; p = strchr(ip, '!'); if(p) *p = 0; t = dnsquery(ds->netdir, ip, "ptr"); for(nt = t; nt != nil; nt = nt->entry) if(strcmp(nt->attr, "dom") == 0){ strcpy(dom, nt->val); ndbfree(t); return 0; } ndbfree(t); return -1; } /* for connection oriented protocols (il, tcp) we just need * to try dialing. resending is up to it. */ static int tcpilprobe(int cfd, int dfd, char *dest, int interval) { int n; char msg[Maxstring]; USED(dfd); n = snprint(msg, sizeof msg, "connect %s", dest); alarm(interval); n = write(cfd, msg, n); alarm(0); return n; } /* * for udp, we keep sending to an improbable port * till we timeout or someone complains */ static int udpprobe(int cfd, int dfd, char *dest, int interval) { int n, i, rv; char msg[Maxstring], err[ERRMAX]; seek(cfd, 0, 0); n = snprint(msg, sizeof msg, "connect %s", dest); if(write(cfd, msg, n)< 0) return -1; rv = -1; for(i = 0; i < 3; i++){ alarm(interval/3); if(write(dfd, "boo hoo ", 8) < 0) break; /* * a hangup due to an error looks like 3 eofs followed * by a real error. this is a qio.c qbread() strangeness * done for pipes. */ do { n = read(dfd, msg, sizeof(msg)-1); } while(n == 0); alarm(0); if(n > 0){ rv = 0; break; } *err = 0; errstr(err, sizeof err); if(strcmp(err, "interrupted") != 0){ errstr(err, sizeof err); break; } errstr(err, sizeof err); } alarm(0); return rv; } #define MSG "traceroute probe" #define MAGIC 0xdead /* ICMPv4 only */ static int icmpprobe(int cfd, int dfd, char *dest, int interval) { int x, i, n, len, rv; char buf[512], err[ERRMAX], msg[Maxstring]; Icmphdr *ip; seek(cfd, 0, 0); n = snprint(msg, sizeof msg, "connect %s", dest); if(write(cfd, msg, n)< 0) return -1; rv = -1; ip = (Icmphdr *)(buf + IPV4HDR_LEN); for(i = 0; i < 3; i++){ alarm(interval/3); ip->type = EchoRequest; ip->code = 0; strcpy((char*)ip->data, MSG); ip->seq[0] = MAGIC; ip->seq[1] = MAGIC>>8; len = IPV4HDR_LEN + ICMP_HDRSIZE + sizeof(MSG); /* send a request */ if(write(dfd, buf, len) < len) break; /* wait for reply */ n = read(dfd, buf, sizeof(buf)); alarm(0); if(n < 0){ *err = 0; errstr(err, sizeof err); if(strcmp(err, "interrupted") != 0){ errstr(err, sizeof err); break; } errstr(err, sizeof err); continue; } x = (ip->seq[1]<<8) | ip->seq[0]; if(n >= len && ip->type == EchoReply && x == MAGIC && strcmp((char*)ip->data, MSG) == 0){ rv = 0; break; } } alarm(0); return rv; } static void catch(void *a, char *msg) { USED(a); if(strstr(msg, "alarm")) noted(NCONT); else noted(NDFLT); } static int call(DS *ds, char *clone, char *dest, int ttl, long *interval) { int cfd, dfd, rv, n; char msg[Maxstring]; char file[Maxstring]; vlong start; notify(catch); /* start timing */ start = nsec()/1000; rv = -1; cfd = open(clone, ORDWR); if(cfd < 0){ werrstr("%s: %r", clone); return -1; } dfd = -1; /* get conversation number */ n = read(cfd, msg, sizeof(msg)-1); if(n <= 0) goto out; msg[n] = 0; /* open data file */ sprint(file, "%s/%s/%s/data", ds->netdir, ds->proto, msg); dfd = open(file, ORDWR); if(dfd < 0) goto out; /* set ttl */ if(ttl) fprint(cfd, "ttl %d", ttl); /* probe */ if(strcmp(ds->proto, "udp") == 0) rv = udpprobe(cfd, dfd, dest, 3000); else if(strcmp(ds->proto, "icmp") == 0) rv = icmpprobe(cfd, dfd, dest, 3000); else /* il and tcp */ rv = tcpilprobe(cfd, dfd, dest, 3000); out: /* turn off alarms */ alarm(0); *interval = nsec()/1000 - start; close(cfd); close(dfd); return rv; } /* * parse a dial string. default netdir is /net. * default proto is tcp. */ static void dial_string_parse(char *str, DS *ds) { char *p, *p2; strncpy(ds->buf, str, Maxstring); ds->buf[Maxstring-3] = 0; p = strchr(ds->buf, '!'); if(p == 0) { ds->netdir = 0; ds->proto = "tcp"; ds->rem = ds->buf; } else { if(*ds->buf != '/'){ ds->netdir = 0; ds->proto = ds->buf; } else { for(p2 = p; *p2 != '/'; p2--) ; *p2++ = 0; ds->netdir = ds->buf; ds->proto = p2; } *p = 0; ds->rem = p + 1; } if(strchr(ds->rem, '!') == 0) strcat(ds->rem, "!32767"); } void main(int argc, char **argv) { int buckets, ttl, j, done, tries, notranslate; long lo, hi, sum, x; long *t; char *net, *p; char clone[Maxpath], dest[Maxstring], hop[Maxstring], dom[Maxstring]; char err[ERRMAX]; DS ds; buckets = 0; tries = 3; notranslate = 0; net = "/net"; ttl = 1; ARGBEGIN{ case 'a': tries = atoi(EARGF(usage())); break; case 'd': debug++; break; case 'h': buckets = atoi(EARGF(usage())); break; case 'n': notranslate++; break; case 't': ttl = atoi(EARGF(usage())); break; case 'x': net = EARGF(usage()); break; default: usage(); }ARGEND; if(argc < 1) usage(); t = malloc(tries*sizeof(ulong)); dial_string_parse(argv[0], &ds); if(ds.netdir == 0) ds.netdir = net; if(csquery(&ds, clone, dest) < 0){ fprint(2, "%s: %s: %r\n", argv0, argv[0]); exits(0); } print("trying %s/%s!%s\n\n", ds.netdir, ds.proto, dest); print(" round trip times in µs\n"); print(" low avg high\n"); print(" --------------------------\n"); done = 0; for(; ttl < 32; ttl++){ for(j = 0; j < tries; j++){ if(call(&ds, clone, dest, ttl, &t[j]) >= 0){ if(debug) print("%ld %s\n", t[j], dest); strcpy(hop, dest); done = 1; continue; } *err = 0; errstr(err, sizeof err); if(strstr(err, "refused")){ strcpy(hop, dest); p = strchr(hop, '!'); if(p) *p = 0; done = 1; } else if(strstr(err, "unreachable")){ snprint(hop, sizeof(hop), "%s", err); p = strchr(hop, '!'); if(p) *p = 0; done = 1; } else if(strncmp(err, "ttl exceeded at ", 16) == 0) strcpy(hop, err+16); else { strcpy(hop, "*"); break; } if(debug) print("%ld %s\n", t[j], hop); } if(strcmp(hop, "*") == 0){ print("*\n"); continue; } lo = 10000000; hi = 0; sum = 0; for(j = 0; j < tries; j++){ x = t[j]; sum += x; if(x < lo) lo = x; if(x > hi) hi = x; } if(notranslate == 1 || dodnsquery(&ds, hop, dom) < 0) dom[0] = 0; /* don't truncate: ipv6 addresses can be quite long */ print("%-18s %8ld %8ld %8ld %s\n", hop, lo, sum/tries, hi, dom); if(buckets) histogram(t, tries, buckets, lo, hi); if(done) break; } exits(0); } char *order = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"; void histogram(long *t, int n, int buckets, long lo, long hi) { int i, j, empty; long span; static char *bar; char *p; char x[64]; if(bar == nil) bar = malloc(n+1); print("+++++++++++++++++++++++\n"); span = (hi-lo)/buckets; span++; empty = 0; for(i = 0; i < buckets; i++){ p = bar; for(j = 0; j < n; j++) if(t[j] >= lo+i*span && t[j] <= lo+(i+1)*span) *p++ = order[j]; *p = 0; if(p != bar){ snprint(x, sizeof x, "[%ld-%ld]", lo+i*span, lo+(i+1)*span); print("%-16s %s\n", x, bar); empty = 0; } else if(!empty){ print("...\n"); empty = 1; } } print("+++++++++++++++++++++++\n"); }