Download | Plain Text | No Line Numbers 

  1. --- /dev/null	1970-01-01 01:00:00.000000000 +0100
  2. +++ CHANGES.tcpserver-limits-patch	2006-01-26 18:59:34.000000000 +0100
  3. @@ -0,0 +1,28 @@
  4. +20060126 Added support for "always reject" (setting MAXCONNIP and/or
  5. +MAXCONNC to 0) and fixing a bug when sometimes DIEMSG would not be 
  6. +shown (by Mark Powell)
  7. +
  8. +20050903 Added support for Solaris (by Jorge Valdes).
  9. +Moved MAXLOAD code to getprocla(). 
  10. +Modified documentation a little to accommodate recent changes.
  11. +
  12. +20050130 reinstated /proc/loadavg support for those compiling on Linux 
  13. +with dietlibc (see #define NO_GETLOADAVG at top of tcpserver.c). 
  14. +Also, we now compile on 64bit platforms (we avoid including unistd.h if
  15. +using getloadavg(3), so we don't conflict with readwrite.h header file)
  16. +Needed if your compile was breaking with:
  17. +readwrite.h:4: error: syntax error before "read"
  18. +readwrite.h:4: warning: data definition has no type or storage class
  19. +SUMMARY: If 20040725 worked for you, there is no reason to upgrade 
  20. +(no new features of bugfixes)
  21. +
  22. +20040725 adds a sleep(1) before terminating (to prevent too high load from
  23. +many rapid fork()/exit() calls. It also changes the method for checking
  24. +system load to getloadavg(3) instead of parsing /proc/loadavg, therefore
  25. +making it working on *BSD and other non-Linux systems in addition to Linux.
  26. +It also adds DIEMSG="xxx" support.
  27. +
  28. +20040327 fixes a bug in 20040124 related to MAXLOAD (it would not work
  29. +correctly when load was higher than 10.00)
  30. +
  31. +
  32. --- /dev/null	1970-01-01 01:00:00.000000000 +0100
  33. +++ README.tcpserver-limits-patch	2006-01-26 18:56:02.000000000 +0100
  34. @@ -0,0 +1,136 @@
  35. +See CHANGES.tcpserver-limits-patch for changes summary.
  36. +
  37. +:::COMPILING:::
  38. +
  39. +    For MAXLOAD variable to have effect, you have 3 options:
  40. +
  41. +(1) By default the patch assumes that you have working getloadavg(3)
  42. +    (most modern UN*Xoids have, including Linux and FreeBSD). No changes
  43. +    are needed to standard ucspi-tcp compilation procedures.
  44. +
  45. +(2) If you have Solaris system:
  46. +    - conf-cc needs to be modified to include "-DSOLARIS"
  47. +    - Makefile needs to be modified so that tcpserver links with "-lkstat" 
  48. +      (add "-lkstat" to the end of line 748 after "`cat socket.lib`")
  49. +
  50. +(3) If you have a non-Solaris system without getloadavg(3), but with 
  51. +    readable '/proc/loadavg' (in linux-2.4.x/2.6.x syntax); for example 
  52. +    if you're compiling on Linux system with dietlibc:
  53. +    - conf-cc needs to be modified to include "-DNO_GETLOADAVG"
  54. +
  55. +
  56. +:::USING:::
  57. +
  58. +This patch (20060126) makes tcpserver from DJB's ucspi-tcp-0.88 package (see
  59. +http://cr.yp.to/ucspi-tcp.html) to modify its behavior if some environment
  60. +variables are present.
  61. +
  62. +The variables can be preset before starting tcpserver (thus acting as
  63. +default for all connections), or, if you use 'tcpserver -x xxx.cdb', they
  64. +can be set (or overridden) from xxx.cdb. If none of the variables are set,
  65. +tcpserver behaves same as non patched version (except for negligible
  66. +performance loss). Any or all variables can be set, as soon as first limit
  67. +is reached the connection is dropped. I'd recommend using .cdb files
  68. +exclusively though, as you can then modify configuration without killing
  69. +tcpserver.
  70. +
  71. +The variables are:
  72. +
  73. +(1) MAXLOAD 
  74. +    maximum 1-minute load average * 100. For example, if you have line
  75. +    :allow,MAXLOAD="350" 
  76. +    in your rules file from which you created .cdb, the connection will be
  77. +    accepted only if load average is below 3.50
  78. +
  79. +    See COMPILING instructions above for info on supported systems.
  80. +  
  81. +(2) MAXCONNIP
  82. +    maximum connections from one IP address. tcpserver's -c flag defines
  83. +    maximum number of allowed connections, but it can be abused if
  84. +    just one host goes wild and eats all the connections - no other host
  85. +    would be able to connect then. If you created your .cdb with:
  86. +    :allow,MAXCONNIP="5"
  87. +    and run tcpserver -c 50, then each IP address would be able to have at 
  88. +    most 5 concurrent connections, while there still could connect 50
  89. +    clients total.
  90. +    0 is valid value and means 'always reject'
  91. +
  92. +(3) MAXCONNC
  93. +
  94. +    maximum connections from whole C-class (256 addresses). Extension of
  95. +    MAXCONNIP, as sometimes the problematic client has a whole farm of
  96. +    client machines with different IP addresses instead of just one IP
  97. +    address, and they all try to connect. It might have been more useful to
  98. +    be able to specify CIDR block than C-class, but I've decided to KISS.
  99. +
  100. +    for example tcpserver -c 200, and .cdb with:
  101. +    :allow,MAXCONNC="15"
  102. +    will allow at most 15 host from any x.y.z.0/24 address block, while
  103. +    still allowing up to 200 total connections.
  104. +    0 is valid value and means 'always reject'
  105. +
  106. +(4) DIEMSG
  107. +    
  108. +    if set and one of the above limits is exceeded, this is the message 
  109. +    to be sent to client (CRLF is always added to the text) before terminating
  110. +    connection. If unset, the connection simply terminates (after 1 sec delay) 
  111. +    if limit is exceeded.
  112. +
  113. +    For example:
  114. +    DIEMSG="421 example.com Service temporarily not available, closing 
  115. +    transmission channel"
  116. +
  117. +Notes: 
  118. +
  119. +- if a connection is dropped due to some of those variables set, it will be
  120. +  flagged (if you run tcpserver -v) with "LOAD:", "MAXCONNIP:" or
  121. +  "MAXCONNC:" at the end of the "tcpserver: deny" line. If that bothers you
  122. +  (eg. you have a strict log parsers), don't apply that chunk of the patch.
  123. +
  124. +- the idea for this patch came from my previous experience with xinetd, and
  125. +  need to limit incoming bursts of virus/spam SMTP connections, since I was
  126. +  running qmail-scanner to scan incoming and outgoing messages for viruses
  127. +  and spam.
  128. +
  129. +When you make changes, please check that they work as expected. 
  130. +
  131. +Examples (for tcprules created .cdb)
  132. +(a) 192.168.:allow,MAXLOAD="1000"
  133. +    :allow,MAXCONNIP="3"
  134. +
  135. +    this would allow any connection from your local LAN (192.168.*.*
  136. +    addresses) if system load is less than 10.00. non-LAN connections would
  137. +    be accepted only if clients from that IP address have not already opened
  138. +    more than 2 connections (as your connection would be last allowed -- 3rd)
  139. +
  140. +(b) 192.168.:allow
  141. +    5.6.7.8:allow,MAXCONNIP="3"
  142. +    1.2.:allow,MAXLOAD="500",MAXCONNIP="1",MAXCONNC="5"
  143. +    :allow,MAXLOAD="1000",MAXCONNIP="3",DIEMSG="421 example.com unavailable"
  144. +
  145. +    if client connects from 192.168.*.* (ex: your LAN), it is allowed.
  146. +    if it connects from 5.6.7.8 (ex: little abusive customer of yours),
  147. +     it is allowed unless there are already 3active connections from 5.6.7.8
  148. +     to this service
  149. +    if it connects from 1.2.*.* (ex: some problematic networks which caused
  150. +     you grief in the past) it will connect only if load is less than 5.0,
  151. +     there is less than 5 active connections from whole C class
  152. +     (1.2.*.0/24), and if that specific IP address does not already have
  153. +     connection open.
  154. +    in all other cases, the client will be permitted to connect if load is
  155. +     less than 10.00 and client has 2 or less connections open. If load is
  156. +     higher than 10.00 or there are 3 or more connections open from this
  157. +     client, the message "421 example.com unavailable" will be returned to 
  158. +     the client and connection terminated.
  159. +
  160. +
  161. +Any bugs introduced are my own, do not bother DJB with them.
  162. +If you find any, or have neat ideas, or better documentation, or whatever,
  163. +contact me.
  164. +
  165. +the latest version of the patch can be found at:
  166. +http://linux.voyager.hr/ucspi-tcp/
  167. +
  168. +Enjoy,
  169. +Matija Nalis,
  170. +mnalis-tcpserver _at_ voyager.hr
  171. --- tcpserver.c	2006-09-12 15:54:11.000000000 +0200
  172. +++ tcpserver.c	2006-09-12 17:59:43.000000000 +0200
  173. @@ -1,3 +1,11 @@
  174. +#ifdef __dietlibc__
  175. +#define NO_GETLOADAVG
  176. +#endif
  177. +
  178. +#include <stdlib.h>
  179. +#ifdef NO_GETLOADAVG
  180. +#include <unistd.h>
  181. +#endif
  182.  #include <sys/types.h>
  183.  #include <sys/param.h>
  184.  #include <netdb.h>
  185. @@ -59,11 +67,29 @@
  186.  static stralloc tmp;
  187.  static stralloc fqdn;
  188.  static stralloc addresses;
  189. +static stralloc diemsg_buf;
  190. +
  191. +#ifdef SOLARIS
  192. +#include <kstat.h>
  193. +static kstat_ctl_t   *kc;
  194. +#ifndef FSCALE
  195. +#define FSHIFT  8               /* bits to right of fixed binary point */
  196. +#define FSCALE  (1<<FSHIFT)
  197. +#endif /* FSCALE */
  198. +
  199. +#define loaddouble(la) ((double)(la) / FSCALE)
  200. +#endif
  201.  
  202.  char bspace[16];
  203.  buffer b;
  204.  
  205. +typedef struct
  206. +{
  207. +  char ip[4];
  208. +  pid_t pid;
  209. +} baby;
  210.  
  211. +baby *child;
  212.  
  213.  /* ---------------------------- child */
  214.  
  215. @@ -72,6 +98,10 @@
  216.  int flagdeny = 0;
  217.  int flagallownorules = 0;
  218.  char *fnrules = 0;
  219. +unsigned long maxload = 0;
  220. +long maxconnip = -1;
  221. +long maxconnc = -1;
  222. +char *diemsg = "";
  223.  
  224.  void drop_nomem(void)
  225.  {
  226. @@ -110,6 +140,8 @@
  227.    strerr_die4sys(111,DROP,"unable to read ",fnrules,": ");
  228.  }
  229.  
  230. +unsigned long limit = 40;
  231. +
  232.  void found(char *data,unsigned int datalen)
  233.  {
  234.    unsigned int next0;
  235. @@ -125,5 +157,13 @@
  236.  	if (data[1 + split] == '=') {
  237.  	  data[1 + split] = 0;
  238.  	  env(data + 1,data + 1 + split + 1);
  239. +	  if (str_diff(data+1, "MAXLOAD") == 0) scan_ulong(data+1+split+1,&maxload);
  240. +	  if (str_diff(data+1, "MAXCONNIP") == 0) scan_ulong(data+1+split+1,&maxconnip);
  241. +	  if (str_diff(data+1, "MAXCONNC") == 0) scan_ulong(data+1+split+1,&maxconnc);
  242. +	  if (str_diff(data+1, "DIEMSG") == 0) {
  243. +	    if (!stralloc_copys(&diemsg_buf,data+1+split+1)) drop_nomem();
  244. +	    if (!stralloc_0(&diemsg_buf)) drop_nomem();
  245. +	    diemsg = diemsg_buf.s;
  246. +	  }
  247.  	}
  248.  	break;
  249. @@ -133,6 +173,49 @@
  250.    }
  251.  }
  252.  
  253. +unsigned long getprocla(void)
  254. +{
  255. +#ifdef SOLARIS
  256. +  kstat_t       *ksp;
  257. +  kstat_named_t *knp;
  258. +  double lavg;
  259. +  kstat_chain_update(kc);
  260. +  ksp = kstat_lookup(kc, "unix", 0, "system_misc");
  261. +  kstat_read(kc,ksp,NULL);
  262. +  knp = kstat_data_lookup(ksp,"avenrun_1min");
  263. +  lavg = loaddouble(knp->value.ui32);
  264. +  return (unsigned long)(lavg * 100);
  265. +#else
  266. +#ifdef NO_GETLOADAVG
  267. +  int lret;
  268. +  int i;
  269. +  unsigned long u1, u2;
  270. +  char *s;
  271. +  static stralloc loadavg_data = {0};
  272. +
  273. +  lret = openreadclose("/proc/loadavg", &loadavg_data, 10);
  274. +  if (lret != -1) {
  275. +    /* /proc/loadavg format is:
  276. +     * 13.08 3.04 1.00 34/170 14190 */
  277. +    s = loadavg_data.s;
  278. +    i = scan_ulong (s, &u1); s+=i;
  279. +    if ((i>0) && (i<5) && (*s == '.')) { /* load should be < 10000 */
  280. +      i = scan_ulong (s+1,&u2);
  281. +      if (i==2) { /* we require two decimal places */
  282. +        return (u1 * 100 + u2);
  283. +      }
  284. +      return (u1 * 100);
  285. +    }
  286. +  }
  287. +#else
  288. +  double result;
  289. +  if (getloadavg(&result, 1) == 1) {
  290. +    return (result * 100);
  291. +  }
  292. +#endif
  293. +#endif
  294. +}
  295. +
  296.  void doit(int t)
  297.  {
  298.    int j;
  299. @@ -211,6 +294,24 @@
  300.      }
  301.    }
  302.  
  303. +  unsigned long curload = 0;
  304. +  if (maxload) {
  305. +    curload = getprocla();
  306. +    if (curload > maxload) flagdeny = 2;
  307. +  }
  308. +
  309. +  if (!flagdeny && (maxconnip != -1 || maxconnc != -1)) {
  310. +    unsigned long u;
  311. +    long c1=0, cc=0;
  312. +    for (u=0; u < limit; u++)
  313. +      if (child[u].pid != 0) {
  314. +	if (byte_equal(child[u].ip, 3, remoteip)) cc++;
  315. +	if (byte_equal(child[u].ip, 4, remoteip)) c1++;
  316. +      }
  317. +      if (maxconnc != -1 && (cc >= maxconnc)) flagdeny = 4;
  318. +      if (maxconnip != -1 && (c1 >= maxconnip)) flagdeny = 3;
  319. +  }
  320. +
  321.    if (verbosity >= 2) {
  322.      strnum[fmt_ulong(strnum,getpid())] = 0;
  323.      if (!stralloc_copys(&tmp,"tcpserver: ")) drop_nomem();
  324. @@ -223,11 +324,35 @@
  325.      cats(":"); safecats(remoteipstr);
  326.      cats(":"); if (flagremoteinfo) safecats(tcpremoteinfo.s);
  327.      cats(":"); safecats(remoteportstr);
  328. +    if (flagdeny == 2) {
  329. +    	char curloadstr[FMT_ULONG];
  330. +    	curloadstr[fmt_ulong(curloadstr,curload)] = 0;
  331. +    	cats(" "); safecats ("LOAD"); cats(":"); safecats(curloadstr);
  332. +    }
  333. +    if (flagdeny == 3) {
  334. +    	char maxconstr[FMT_ULONG];
  335. +    	maxconstr[fmt_ulong(maxconstr,maxconnip)] = 0;
  336. +    	cats(" "); safecats ("MAXCONNIP"); cats(":"); safecats(maxconstr);
  337. +    }
  338. +    if (flagdeny == 4) {
  339. +    	char maxconstr[FMT_ULONG];
  340. +    	maxconstr[fmt_ulong(maxconstr,maxconnc)] = 0;
  341. +    	cats(" "); safecats ("MAXCONNC"); cats(":"); safecats(maxconstr);
  342. +    }
  343.      cats("\n");
  344.      buffer_putflush(buffer_2,tmp.s,tmp.len);
  345.    }
  346.  
  347. -  if (flagdeny) _exit(100);
  348. +  if (flagdeny) {
  349. +    if (*diemsg) {
  350. +      buffer_init(&b,write,t,bspace,sizeof bspace);
  351. +      buffer_puts(&b,diemsg);
  352. +      if (buffer_putsflush(&b,"\r\n") == -1)
  353. +        strerr_die2sys(111,DROP,"unable to print diemsg: ");
  354. +    }
  355. +    sleep(1);
  356. +    _exit(100);
  357. +  }
  358.  }
  359.  
  360.  
  361. @@ -253,7 +378,6 @@
  362.    _exit(100);
  363.  }
  364.  
  365. -unsigned long limit = 40;
  366.  unsigned long numchildren = 0;
  367.  
  368.  int flag1 = 0;
  369. @@ -278,6 +402,7 @@
  370.  {
  371.    int wstat;
  372.    int pid;
  373. +  unsigned long u;
  374.  
  375.    while ((pid = wait_nohang(&wstat)) > 0) {
  376.      if (verbosity >= 2) {
  377. @@ -286,11 +411,14 @@
  378.        strerr_warn4("tcpserver: end ",strnum," status ",strnum2,0);
  379.      }
  380.      if (numchildren) --numchildren; printstatus();
  381. +    for (u=0; u < limit; u++) if (child[u].pid == pid) { child[u].pid = 0; break; }
  382. +    if (u == limit) strerr_die1x(111,"tcpserver: ERROR: dead child not found?!"); /* never happens */
  383.    }
  384.  }
  385.  
  386.  main(int argc,char **argv)
  387.  {
  388. +  pid_t pid;
  389.    char *hostname;
  390.    char *portname;
  391.    int opt;
  392. @@ -331,6 +459,10 @@
  393.      }
  394.    argc -= optind;
  395.    argv += optind;
  396. +  x = env_get("MAXLOAD"); if (x) scan_ulong(x,&maxload);
  397. +  x = env_get("MAXCONNIP"); if (x) scan_ulong(x,&maxconnip);
  398. +  x = env_get("MAXCONNC"); if (x) scan_ulong(x,&maxconnc);
  399. +  x = env_get("DIEMSG"); if (x) diemsg = x;
  400.  
  401.    if (!verbosity)
  402.      buffer_2->fd = -1;
  403. @@ -352,6 +484,10 @@
  404.    }
  405.  
  406.    if (!*argv) usage();
  407. +
  408. +  child = calloc(sizeof(baby),limit);
  409. +  if (!child)
  410. +    strerr_die2x(111,FATAL,"out of memory for MAXCONNIP tracking");
  411.  
  412.    sig_block(sig_child);
  413.    sig_catch(sig_child,sigchld);
  414. @@ -393,6 +529,9 @@
  415.  
  416.    close(0);
  417.    close(1);
  418. +  #ifdef SOLARIS
  419. +  kc = kstat_open();
  420. +  #endif
  421.    printstatus();
  422.  
  423.    for (;;) {
  424. @@ -405,7 +544,7 @@
  425.      if (t == -1) continue;
  426.      ++numchildren; printstatus();
  427.  
  428. -    switch(fork()) {
  429. +    switch(pid=fork()) {
  430.        case 0:
  431.          close(s);
  432.          doit(t);
  433. @@ -420,6 +559,16 @@
  434.        case -1:
  435.          strerr_warn2(DROP,"unable to fork: ",&strerr_sys);
  436.          --numchildren; printstatus();
  437. +        break;
  438. +      default:
  439. +        for (u=0; u < limit; u++)
  440. +	  if (child[u].pid == 0) {
  441. +	    byte_copy(child[u].ip,4,remoteip);
  442. +	    child[u].pid = pid;
  443. +	    break;
  444. +	  }
  445. +	if (u == limit)
  446. +	  strerr_die1x(111,"tcpserver: ERROR: no empty space for new child?!"); /* never happens */
  447.      }
  448.      close(t);
  449.    }
  450.