misc/nstat.c

   1 /*
   2  * nstat.c      handy utility to read counters /proc/net/netstat and snmp
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  */
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <unistd.h>
  15 #include <fcntl.h>
  16 #include <string.h>
  17 #include <errno.h>
  18 #include <time.h>
  19 #include <sys/time.h>
  20 #include <fnmatch.h>
  21 #include <sys/file.h>
  22 #include <sys/socket.h>
  23 #include <sys/un.h>
  24 #include <sys/poll.h>
  25 #include <sys/wait.h>
  26 #include <sys/stat.h>
  27 #include <signal.h>
  28 #include <math.h>
  29
  30 #include <SNAPSHOT.h>
  31
  32 int dump_zeros = 0;
  33 int reset_history = 0;
  34 int ignore_history = 0;
  35 int no_output = 0;
  36 int no_update = 0;
  37 int scan_interval = 0;
  38 int time_constant = 0;
  39 double W;
  40 char **patterns;
  41 int npatterns;
  42
  43 char info_source[128];
  44 int source_mismatch;
  45
  46 int generic_proc_open(char *env, char *name)
  47 {
  48         char store[128];
  49         char *p = getenv(env);
  50         if (!p) {
  51                 p = getenv("PROC_ROOT") ? : "/proc";
  52                 snprintf(store, sizeof(store)-1, "%s/%s", p, name);
  53                 p = store;
  54         }
  55         return open(store, O_RDONLY);
  56 }
  57
  58 int net_netstat_open(void)
  59 {
  60         return generic_proc_open("PROC_NET_NETSTAT", "net/netstat");
  61 }
  62
  63 int net_snmp_open(void)
  64 {
  65         return generic_proc_open("PROC_NET_SNMP", "net/snmp");
  66 }
  67
  68 int net_snmp6_open(void)
  69 {
  70         return generic_proc_open("PROC_NET_SNMP6", "net/snmp6");
  71 }
  72
  73 struct nstat_ent
  74 {
  75         struct nstat_ent *next;
  76         char             *id;
  77         unsigned long long val;
  78         unsigned long      ival;
  79         double             rate;
  80 };
  81
  82 struct nstat_ent *kern_db;
  83 struct nstat_ent *hist_db;
  84
  85 char *useless_numbers[] = {
  86 "IpForwarding", "IpDefaultTTL",
  87 "TcpRtoAlgorithm", "TcpRtoMin", "TcpRtoMax",
  88 "TcpMaxConn", "TcpCurrEstab"
  89 };
  90
  91 int useless_number(char *id)
  92 {
  93         int i;
  94         for (i=0; i<sizeof(useless_numbers)/sizeof(*useless_numbers); i++)
  95                 if (strcmp(id, useless_numbers[i]) == 0)
  96                         return 1;
  97         return 0;
  98 }
  99
 100 int match(char *id)
 101 {
 102         int i;
 103
 104         if (npatterns == 0)
 105                 return 1;
 106
 107         for (i=0; i<npatterns; i++) {
 108                 if (!fnmatch(patterns[i], id, 0))
 109                         return 1;
 110         }
 111         return 0;
 112 }
 113
 114 void load_good_table(FILE *fp)
 115 {
 116         char buf[4096];
 117         struct nstat_ent *db = NULL;
 118         struct nstat_ent *n;
 119
 120         while (fgets(buf, sizeof(buf), fp) != NULL) {
 121                 int nr;
 122                 unsigned long long val;
 123                 double rate;
 124                 char idbuf[sizeof(buf)];
 125                 if (buf[0] == '#') {
 126                         buf[strlen(buf)-1] = 0;
 127                         if (info_source[0] && strcmp(info_source, buf+1))
 128                                 source_mismatch = 1;
 129                         info_source[0] = 0;
 130                         strncat(info_source, buf+1, sizeof(info_source)-1);
 131                         continue;
 132                 }
 133                 /* idbuf is as big as buf, so this is safe */
 134                 nr = sscanf(buf, "%s%llu%lg", idbuf, &val, &rate);
 135                 if (nr < 2)
 136                         abort();
 137                 if (nr < 3)
 138                         rate = 0;
 139                 if (useless_number(idbuf))
 140                         continue;
 141                 if ((n = malloc(sizeof(*n))) == NULL)
 142                         abort();
 143                 n->id = strdup(idbuf);
 144                 n->ival = (unsigned long)val;
 145                 n->val = val;
 146                 n->rate = rate;
 147                 n->next = db;
 148                 db = n;
 149         }
 150
 151         while (db) {
 152                 n = db;
 153                 db = db->next;
 154                 n->next = kern_db;
 155                 kern_db = n;
 156         }
 157 }
 158
 159
 160 void load_ugly_table(FILE *fp)
 161 {
 162         char buf[4096];
 163         struct nstat_ent *db = NULL;
 164         struct nstat_ent *n;
 165
 166         while (fgets(buf, sizeof(buf), fp) != NULL) {
 167                 char idbuf[sizeof(buf)];
 168                 int  off;
 169                 char *p;
 170
 171                 p = strchr(buf, ':');
 172                 if (!p)
 173                         abort();
 174                 *p = 0;
 175                 idbuf[0] = 0;
 176                 strncat(idbuf, buf, sizeof(idbuf) - 1);
 177                 off = p - buf;
 178                 p += 2;
 179
 180                 while (*p) {
 181                         char *next;
 182                         if ((next = strchr(p, ' ')) != NULL)
 183                                 *next++ = 0;
 184                         else if ((next = strchr(p, '\n')) != NULL)
 185                                 *next++ = 0;
 186                         if (off < sizeof(idbuf)) {
 187                                 idbuf[off] = 0;
 188                                 strncat(idbuf, p, sizeof(idbuf) - off - 1);
 189                         }
 190                         n = malloc(sizeof(*n));
 191                         if (!n)
 192                                 abort();
 193                         n->id = strdup(idbuf);
 194                         n->rate = 0;
 195                         n->next = db;
 196                         db = n;
 197                         p = next;
 198                 }
 199                 n = db;
 200                 if (fgets(buf, sizeof(buf), fp) == NULL)
 201                         abort();
 202                 do {
 203                         p = strrchr(buf, ' ');
 204                         if (!p)
 205                                 abort();
 206                         *p = 0;
 207                         if (sscanf(p+1, "%lu", &n->ival) != 1)
 208                                 abort();
 209                         n->val = n->ival;
 210                         /* Trick to skip "dummy" trailing ICMP MIB in 2.4 */
 211                         if (strcmp(idbuf, "IcmpOutAddrMaskReps") == 0)
 212                                 idbuf[5] = 0;
 213                         else
 214                                 n = n->next;
 215                 } while (p > buf + off + 2);
 216         }
 217
 218         while (db) {
 219                 n = db;
 220                 db = db->next;
 221                 if (useless_number(n->id)) {
 222                         free(n->id);
 223                         free(n);
 224                 } else {
 225                         n->next = kern_db;
 226                         kern_db = n;
 227                 }
 228         }
 229 }
 230
 231 void load_snmp(void)
 232 {
 233         FILE *fp = fdopen(net_snmp_open(), "r");
 234         if (fp) {
 235                 load_ugly_table(fp);
 236                 fclose(fp);
 237         }
 238 }
 239
 240 void load_snmp6(void)
 241 {
 242         FILE *fp = fdopen(net_snmp6_open(), "r");
 243         if (fp) {
 244                 load_good_table(fp);
 245                 fclose(fp);
 246         }
 247 }
 248
 249 void load_netstat(void)
 250 {
 251         FILE *fp = fdopen(net_netstat_open(), "r");
 252         if (fp) {
 253                 load_ugly_table(fp);
 254                 fclose(fp);
 255         }
 256 }
 257
 258 void dump_kern_db(FILE *fp, int to_hist)
 259 {
 260         struct nstat_ent *n, *h;
 261         h = hist_db;
 262         fprintf(fp, "#%s\n", info_source);
 263         for (n=kern_db; n; n=n->next) {
 264                 unsigned long long val = n->val;
 265                 if (!dump_zeros && !val && !n->rate)
 266                         continue;
 267                 if (!match(n->id)) {
 268                         struct nstat_ent *h1;
 269                         if (!to_hist)
 270                                 continue;
 271                         for (h1 = h; h1; h1 = h1->next) {
 272                                 if (strcmp(h1->id, n->id) == 0) {
 273                                         val = h1->val;
 274                                         h = h1->next;
 275                                         break;
 276                                 }
 277                         }
 278                 }
 279                 fprintf(fp, "%-32s%-16llu%6.1f\n", n->id, val, n->rate);
 280         }
 281 }
 282
 283 void dump_incr_db(FILE *fp)
 284 {
 285         struct nstat_ent *n, *h;
 286         h = hist_db;
 287         fprintf(fp, "#%s\n", info_source);
 288         for (n=kern_db; n; n=n->next) {
 289                 int ovfl = 0;
 290                 unsigned long long val = n->val;
 291                 struct nstat_ent *h1;
 292                 for (h1 = h; h1; h1 = h1->next) {
 293                         if (strcmp(h1->id, n->id) == 0) {
 294                                 if (val < h1->val) {
 295                                         ovfl = 1;
 296                                         val = h1->val;
 297                                 }
 298                                 val -= h1->val;
 299                                 h = h1->next;
 300                                 break;
 301                         }
 302                 }
 303                 if (!dump_zeros && !val && !n->rate)
 304                         continue;
 305                 if (!match(n->id))
 306                         continue;
 307                 fprintf(fp, "%-32s%-16llu%6.1f%s\n", n->id, val,
 308                         n->rate, ovfl?" (overflow)":"");
 309         }
 310 }
 311
 312 static int children;
 313
 314 void sigchild(int signo)
 315 {
 316 }
 317
 318 void update_db(int interval)
 319 {
 320         struct nstat_ent *n, *h;
 321
 322         n = kern_db;
 323         kern_db = NULL;
 324
 325         load_netstat();
 326         load_snmp6();
 327         load_snmp();
 328
 329         h = kern_db;
 330         kern_db = n;
 331
 332         for (n = kern_db; n; n = n->next) {
 333                 struct nstat_ent *h1;
 334                 for (h1 = h; h1; h1 = h1->next) {
 335                         if (strcmp(h1->id, n->id) == 0) {
 336                                 double sample;
 337                                 unsigned long incr = h1->ival - n->ival;
 338                                 n->val += incr;
 339                                 n->ival = h1->ival;
 340                                 sample = (double)(incr*1000)/interval;
 341                                 if (interval >= scan_interval) {
 342                                         n->rate += W*(sample-n->rate);
 343                                 } else if (interval >= 1000) {
 344                                         if (interval >= time_constant) {
 345                                                 n->rate = sample;
 346                                         } else {
 347                                                 double w = W*(double)interval/scan_interval;
 348                                                 n->rate += w*(sample-n->rate);
 349                                         }
 350                                 }
 351
 352                                 while (h != h1) {
 353                                         struct nstat_ent *tmp = h;
 354                                         h = h->next;
 355                                         free(tmp->id);
 356                                         free(tmp);
 357                                 };
 358                                 h = h1->next;
 359                                 free(h1->id);
 360                                 free(h1);
 361                                 break;
 362                         }
 363                 }
 364         }
 365 }
 366
 367 #define T_DIFF(a,b) (((a).tv_sec-(b).tv_sec)*1000 + ((a).tv_usec-(b).tv_usec)/1000)
 368
 369
 370 void server_loop(int fd)
 371 {
 372         struct timeval snaptime;
 373         struct pollfd p;
 374         p.fd = fd;
 375         p.events = p.revents = POLLIN;
 376
 377         sprintf(info_source, "%d.%lu sampling_interval=%d time_const=%d",
 378                 getpid(), (unsigned long)random(), scan_interval/1000, time_constant/1000);
 379
 380         load_netstat();
 381         load_snmp6();
 382         load_snmp();
 383
 384         for (;;) {
 385                 int status;
 386                 int tdiff;
 387                 struct timeval now;
 388                 gettimeofday(&now, NULL);
 389                 tdiff = T_DIFF(now, snaptime);
 390                 if (tdiff >= scan_interval) {
 391                         update_db(tdiff);
 392                         snaptime = now;
 393                         tdiff = 0;
 394                 }
 395                 if (poll(&p, 1, tdiff + scan_interval) > 0
 396                     && (p.revents&POLLIN)) {
 397                         int clnt = accept(fd, NULL, NULL);
 398                         if (clnt >= 0) {
 399                                 pid_t pid;
 400                                 if (children >= 5) {
 401                                         close(clnt);
 402                                 } else if ((pid = fork()) != 0) {
 403                                         if (pid>0)
 404                                                 children++;
 405                                         close(clnt);
 406                                 } else {
 407                                         FILE *fp = fdopen(clnt, "w");
 408                                         if (fp) {
 409                                                 if (tdiff > 0)
 410                                                         update_db(tdiff);
 411                                                 dump_kern_db(fp, 0);
 412                                         }
 413                                         exit(0);
 414                                 }
 415                         }
 416                 }
 417                 while (children && waitpid(-1, &status, WNOHANG) > 0)
 418                         children--;
 419         }
 420 }
 421
 422 int verify_forging(int fd)
 423 {
 424         struct ucred cred;
 425         int olen = sizeof(cred);
 426         if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, (void*)&cred, &olen) ||
 427             olen < sizeof(cred))
 428                 return -1;
 429         if (cred.uid == getuid() || cred.uid == 0)
 430                 return 0;
 431         return -1;
 432 }
 433
 434 static void usage(void) __attribute__((noreturn));
 435
 436 static void usage(void)
 437 {
 438         fprintf(stderr,
 439 "Usage: nstat [ -h?vVzrnasd:t: ] [ PATTERN [ PATTERN ] ]\n"
 440                 );
 441         exit(-1);
 442 }
 443
 444
 445 int main(int argc, char *argv[])
 446 {
 447         char hist_name[128];
 448         struct sockaddr_un sun;
 449         FILE *hist_fp = NULL;
 450         int ch;
 451         int fd;
 452
 453         while ((ch = getopt(argc, argv, "h?vVzrnasd:t:")) != EOF) {
 454                 switch(ch) {
 455                 case 'z':
 456                         dump_zeros = 1;
 457                         break;
 458                 case 'r':
 459                         reset_history = 1;
 460                         break;
 461                 case 'a':
 462                         ignore_history = 1;
 463                         break;
 464                 case 's':
 465                         no_update = 1;
 466                         break;
 467                 case 'n':
 468                         no_output = 1;
 469                         break;
 470                 case 'd':
 471                         scan_interval = 1000*atoi(optarg);
 472                         break;
 473                 case 't':
 474                         if (sscanf(optarg, "%d", &time_constant) != 1 ||
 475                             time_constant <= 0) {
 476                                 fprintf(stderr, "nstat: invalid time constant divisor\n");
 477                                 exit(-1);
 478                         }
 479                         break;
 480                 case 'v':
 481                 case 'V':
 482                         printf("nstat utility, iproute2-ss%s\n", SNAPSHOT);
 483                         exit(0);
 484                 case 'h':
 485                 case '?':
 486                 default:
 487                         usage();
 488                 }
 489         }
 490
 491         argc -= optind;
 492         argv += optind;
 493
 494         sun.sun_family = AF_UNIX;
 495         sun.sun_path[0] = 0;
 496         sprintf(sun.sun_path+1, "nstat%d", getuid());
 497
 498         if (scan_interval > 0) {
 499                 if (time_constant == 0)
 500                         time_constant = 60;
 501                 time_constant *= 1000;
 502                 W = 1 - 1/exp(log(10)*(double)scan_interval/time_constant);
 503                 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
 504                         perror("nstat: socket");
 505                         exit(-1);
 506                 }
 507                 if (bind(fd, (struct sockaddr*)&sun, 2+1+strlen(sun.sun_path+1)) < 0) {
 508                         perror("nstat: bind");
 509                         exit(-1);
 510                 }
 511                 if (listen(fd, 5) < 0) {
 512                         perror("nstat: listen");
 513                         exit(-1);
 514                 }
 515                 if (fork())
 516                         exit(0);
 517                 chdir("/");
 518                 close(0); close(1); close(2); setsid();
 519                 signal(SIGPIPE, SIG_IGN);
 520                 signal(SIGCHLD, sigchild);
 521                 server_loop(fd);
 522                 exit(0);
 523         }
 524
 525         patterns = argv;
 526         npatterns = argc;
 527
 528         if (getenv("NSTAT_HISTORY"))
 529                 snprintf(hist_name, sizeof(hist_name), getenv("NSTAT_HISTORY"));
 530         else
 531                 sprintf(hist_name, "/tmp/.nstat.u%d", getuid());
 532
 533         if (reset_history)
 534                 unlink(hist_name);
 535
 536         if (!ignore_history || !no_update) {
 537                 struct stat stb;
 538
 539                 fd = open(hist_name, O_RDWR|O_CREAT|O_NOFOLLOW, 0600);
 540                 if (fd < 0) {
 541                         perror("nstat: open history file");
 542                         exit(-1);
 543                 }
 544                 if ((hist_fp = fdopen(fd, "r+")) == NULL) {
 545                         perror("nstat: fdopen history file");
 546                         exit(-1);
 547                 }
 548                 if (flock(fileno(hist_fp), LOCK_EX)) {
 549                         perror("nstat: flock history file");
 550                         exit(-1);
 551                 }
 552                 if (fstat(fileno(hist_fp), &stb) != 0) {
 553                         perror("nstat: fstat history file");
 554                         exit(-1);
 555                 }
 556                 if (stb.st_nlink != 1 || stb.st_uid != getuid()) {
 557                         fprintf(stderr, "nstat: something is so wrong with history file, that I prefer not to proceed.\n");
 558                         exit(-1);
 559                 }
 560                 if (!ignore_history) {
 561                         FILE *tfp;
 562                         long uptime;
 563                         if ((tfp = fopen("/proc/uptime", "r")) != NULL) {
 564                                 if (fscanf(tfp, "%ld", &uptime) != 1)
 565                                         uptime = -1;
 566                                 fclose(tfp);
 567                         }
 568                         if (uptime >= 0 && time(NULL) >= stb.st_mtime+uptime) {
 569                                 fprintf(stderr, "nstat: history is aged out, resetting\n");
 570                                 ftruncate(fileno(hist_fp), 0);
 571                         }
 572                 }
 573
 574                 load_good_table(hist_fp);
 575
 576                 hist_db = kern_db;
 577                 kern_db = NULL;
 578         }
 579
 580         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) >= 0 &&
 581             (connect(fd, (struct sockaddr*)&sun, 2+1+strlen(sun.sun_path+1)) == 0
 582              || (strcpy(sun.sun_path+1, "nstat0"),
 583                  connect(fd, (struct sockaddr*)&sun, 2+1+strlen(sun.sun_path+1)) == 0))
 584             && verify_forging(fd) == 0) {
 585                 FILE *sfp = fdopen(fd, "r");
 586                 load_good_table(sfp);
 587                 if (hist_db && source_mismatch) {
 588                         fprintf(stderr, "nstat: history is stale, ignoring it.\n");
 589                         hist_db = NULL;
 590                 }
 591                 fclose(sfp);
 592         } else {
 593                 if (fd >= 0)
 594                         close(fd);
 595                 if (hist_db && info_source[0] && strcmp(info_source, "kernel")) {
 596                         fprintf(stderr, "nstat: history is stale, ignoring it.\n");
 597                         hist_db = NULL;
 598                         info_source[0] = 0;
 599                 }
 600                 load_netstat();
 601                 load_snmp6();
 602                 load_snmp();
 603                 if (info_source[0] == 0)
 604                         strcpy(info_source, "kernel");
 605         }
 606
 607         if (!no_output) {
 608                 if (ignore_history || hist_db == NULL)
 609                         dump_kern_db(stdout, 0);
 610                 else
 611                         dump_incr_db(stdout);
 612         }
 613         if (!no_update) {
 614                 ftruncate(fileno(hist_fp), 0);
 615                 rewind(hist_fp);
 616                 dump_kern_db(hist_fp, 1);
 617                 fflush(hist_fp);
 618         }
 619         exit(0);
 620 }