The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/netinet/accf_http.c

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    1 /*-
    2  * Copyright (c) 2000 Paycounter, Inc.
    3  * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
    4  * All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   25  * SUCH DAMAGE.
   26  */
   27 
   28 #include <sys/cdefs.h>
   29 __FBSDID("$FreeBSD: releng/10.2/sys/netinet/accf_http.c 227309 2011-11-07 15:43:11Z ed $");
   30 
   31 #define ACCEPT_FILTER_MOD
   32 
   33 #include <sys/param.h>
   34 #include <sys/kernel.h>
   35 #include <sys/mbuf.h>
   36 #include <sys/module.h>
   37 #include <sys/signalvar.h>
   38 #include <sys/sysctl.h>
   39 #include <sys/socketvar.h>
   40 
   41 /* check for GET/HEAD */
   42 static int sohashttpget(struct socket *so, void *arg, int waitflag);
   43 /* check for HTTP/1.0 or HTTP/1.1 */
   44 static int soparsehttpvers(struct socket *so, void *arg, int waitflag);
   45 /* check for end of HTTP/1.x request */
   46 static int soishttpconnected(struct socket *so, void *arg, int waitflag);
   47 /* strcmp on an mbuf chain */
   48 static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp);
   49 /* strncmp on an mbuf chain */
   50 static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset,
   51         int max, char *cmp);
   52 /* socketbuffer is full */
   53 static int sbfull(struct sockbuf *sb);
   54 
   55 static struct accept_filter accf_http_filter = {
   56         "httpready",
   57         sohashttpget,
   58         NULL,
   59         NULL
   60 };
   61 
   62 static moduledata_t accf_http_mod = {
   63         "accf_http",
   64         accept_filt_generic_mod_event,
   65         &accf_http_filter
   66 };
   67 
   68 DECLARE_MODULE(accf_http, accf_http_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
   69 
   70 static int parse_http_version = 1;
   71 
   72 static SYSCTL_NODE(_net_inet_accf, OID_AUTO, http, CTLFLAG_RW, 0,
   73 "HTTP accept filter");
   74 SYSCTL_INT(_net_inet_accf_http, OID_AUTO, parsehttpversion, CTLFLAG_RW,
   75 &parse_http_version, 1,
   76 "Parse http version so that non 1.x requests work");
   77 
   78 #ifdef ACCF_HTTP_DEBUG
   79 #define DPRINT(fmt, args...)                                            \
   80         do {                                                            \
   81                 printf("%s:%d: " fmt "\n", __func__, __LINE__, ##args); \
   82         } while (0)
   83 #else
   84 #define DPRINT(fmt, args...)
   85 #endif
   86 
   87 static int
   88 sbfull(struct sockbuf *sb)
   89 {
   90 
   91         DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, "
   92             "mbcnt(%ld) >= mbmax(%ld): %d",
   93             sb->sb_cc, sb->sb_hiwat, sb->sb_cc >= sb->sb_hiwat,
   94             sb->sb_mbcnt, sb->sb_mbmax, sb->sb_mbcnt >= sb->sb_mbmax);
   95         return (sb->sb_cc >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax);
   96 }
   97 
   98 /*
   99  * start at mbuf m, (must provide npkt if exists)
  100  * starting at offset in m compare characters in mbuf chain for 'cmp'
  101  */
  102 static int
  103 mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp)
  104 {
  105         struct mbuf *n;
  106 
  107         for (; m != NULL; m = n) {
  108                 n = npkt;
  109                 if (npkt)
  110                         npkt = npkt->m_nextpkt;
  111                 for (; m; m = m->m_next) {
  112                         for (; offset < m->m_len; offset++, cmp++) {
  113                                 if (*cmp == '\0')
  114                                         return (1);
  115                                 else if (*cmp != *(mtod(m, char *) + offset))
  116                                         return (0);
  117                         }
  118                         if (*cmp == '\0')
  119                                 return (1);
  120                         offset = 0;
  121                 }
  122         }
  123         return (0);
  124 }
  125 
  126 /*
  127  * start at mbuf m, (must provide npkt if exists)
  128  * starting at offset in m compare characters in mbuf chain for 'cmp'
  129  * stop at 'max' characters
  130  */
  131 static int
  132 mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int max, char *cmp)
  133 {
  134         struct mbuf *n;
  135 
  136         for (; m != NULL; m = n) {
  137                 n = npkt;
  138                 if (npkt)
  139                         npkt = npkt->m_nextpkt;
  140                 for (; m; m = m->m_next) {
  141                         for (; offset < m->m_len; offset++, cmp++, max--) {
  142                                 if (max == 0 || *cmp == '\0')
  143                                         return (1);
  144                                 else if (*cmp != *(mtod(m, char *) + offset))
  145                                         return (0);
  146                         }
  147                         if (max == 0 || *cmp == '\0')
  148                                 return (1);
  149                         offset = 0;
  150                 }
  151         }
  152         return (0);
  153 }
  154 
  155 #define STRSETUP(sptr, slen, str)                                       \
  156         do {                                                            \
  157                 sptr = str;                                             \
  158                 slen = sizeof(str) - 1;                                 \
  159         } while(0)
  160 
  161 static int
  162 sohashttpget(struct socket *so, void *arg, int waitflag)
  163 {
  164 
  165         if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) {
  166                 struct mbuf *m;
  167                 char *cmp;
  168                 int     cmplen, cc;
  169 
  170                 m = so->so_rcv.sb_mb;
  171                 cc = so->so_rcv.sb_cc - 1;
  172                 if (cc < 1)
  173                         return (SU_OK);
  174                 switch (*mtod(m, char *)) {
  175                 case 'G':
  176                         STRSETUP(cmp, cmplen, "ET ");
  177                         break;
  178                 case 'H':
  179                         STRSETUP(cmp, cmplen, "EAD ");
  180                         break;
  181                 default:
  182                         goto fallout;
  183                 }
  184                 if (cc < cmplen) {
  185                         if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) {
  186                                 DPRINT("short cc (%d) but mbufstrncmp ok", cc);
  187                                 return (SU_OK);
  188                         } else {
  189                                 DPRINT("short cc (%d) mbufstrncmp failed", cc);
  190                                 goto fallout;
  191                         }
  192                 }
  193                 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) {
  194                         DPRINT("mbufstrcmp ok");
  195                         if (parse_http_version == 0)
  196                                 return (soishttpconnected(so, arg, waitflag));
  197                         else
  198                                 return (soparsehttpvers(so, arg, waitflag));
  199                 }
  200                 DPRINT("mbufstrcmp bad");
  201         }
  202 
  203 fallout:
  204         DPRINT("fallout");
  205         return (SU_ISCONNECTED);
  206 }
  207 
  208 static int
  209 soparsehttpvers(struct socket *so, void *arg, int waitflag)
  210 {
  211         struct mbuf *m, *n;
  212         int     i, cc, spaces, inspaces;
  213 
  214         if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
  215                 goto fallout;
  216 
  217         m = so->so_rcv.sb_mb;
  218         cc = so->so_rcv.sb_cc;
  219         inspaces = spaces = 0;
  220         for (m = so->so_rcv.sb_mb; m; m = n) {
  221                 n = m->m_nextpkt;
  222                 for (; m; m = m->m_next) {
  223                         for (i = 0; i < m->m_len; i++, cc--) {
  224                                 switch (*(mtod(m, char *) + i)) {
  225                                 case ' ':
  226                                         /* tabs? '\t' */
  227                                         if (!inspaces) {
  228                                                 spaces++;
  229                                                 inspaces = 1;
  230                                         }
  231                                         break;
  232                                 case '\r':
  233                                 case '\n':
  234                                         DPRINT("newline");
  235                                         goto fallout;
  236                                 default:
  237                                         if (spaces != 2) {
  238                                                 inspaces = 0;
  239                                                 break;
  240                                         }
  241 
  242                                         /*
  243                                          * if we don't have enough characters
  244                                          * left (cc < sizeof("HTTP/1.0") - 1)
  245                                          * then see if the remaining ones
  246                                          * are a request we can parse.
  247                                          */
  248                                         if (cc < sizeof("HTTP/1.0") - 1) {
  249                                                 if (mbufstrncmp(m, n, i, cc,
  250                                                         "HTTP/1.") == 1) {
  251                                                         DPRINT("ok");
  252                                                         goto readmore;
  253                                                 } else {
  254                                                         DPRINT("bad");
  255                                                         goto fallout;
  256                                                 }
  257                                         } else if (
  258                                             mbufstrcmp(m, n, i, "HTTP/1.0") ||
  259                                             mbufstrcmp(m, n, i, "HTTP/1.1")) {
  260                                                 DPRINT("ok");
  261                                                 return (soishttpconnected(so,
  262                                                     arg, waitflag));
  263                                         } else {
  264                                                 DPRINT("bad");
  265                                                 goto fallout;
  266                                         }
  267                                 }
  268                         }
  269                 }
  270         }
  271 readmore:
  272         DPRINT("readmore");
  273         /*
  274          * if we hit here we haven't hit something
  275          * we don't understand or a newline, so try again
  276          */
  277         soupcall_set(so, SO_RCV, soparsehttpvers, arg);
  278         return (SU_OK);
  279 
  280 fallout:
  281         DPRINT("fallout");
  282         return (SU_ISCONNECTED);
  283 }
  284 
  285 
  286 #define NCHRS 3
  287 
  288 static int
  289 soishttpconnected(struct socket *so, void *arg, int waitflag)
  290 {
  291         char a, b, c;
  292         struct mbuf *m, *n;
  293         int ccleft, copied;
  294 
  295         DPRINT("start");
  296         if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
  297                 goto gotit;
  298 
  299         /*
  300          * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c
  301          * copied - how much we've copied so far
  302          * ccleft - how many bytes remaining in the socketbuffer
  303          * just loop over the mbufs subtracting from 'ccleft' until we only
  304          * have NCHRS left
  305          */
  306         copied = 0;
  307         ccleft = so->so_rcv.sb_cc;
  308         if (ccleft < NCHRS)
  309                 goto readmore;
  310         a = b = c = '\0';
  311         for (m = so->so_rcv.sb_mb; m; m = n) {
  312                 n = m->m_nextpkt;
  313                 for (; m; m = m->m_next) {
  314                         ccleft -= m->m_len;
  315                         if (ccleft <= NCHRS) {
  316                                 char *src;
  317                                 int tocopy;
  318 
  319                                 tocopy = (NCHRS - ccleft) - copied;
  320                                 src = mtod(m, char *) + (m->m_len - tocopy);
  321 
  322                                 while (tocopy--) {
  323                                         switch (copied++) {
  324                                         case 0:
  325                                                 a = *src++;
  326                                                 break;
  327                                         case 1:
  328                                                 b = *src++;
  329                                                 break;
  330                                         case 2:
  331                                                 c = *src++;
  332                                                 break;
  333                                         }
  334                                 }
  335                         }
  336                 }
  337         }
  338         if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) {
  339                 /* we have all request headers */
  340                 goto gotit;
  341         }
  342 
  343 readmore:
  344         soupcall_set(so, SO_RCV, soishttpconnected, arg);
  345         return (SU_OK);
  346 
  347 gotit:
  348         return (SU_ISCONNECTED);
  349 }

Cache object: b7d19fb6ca5298c9208450eba7fa6e97


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