sys/net/accf_http/accf_http.c

   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  *      $FreeBSD: src/sys/netinet/accf_http.c,v 1.1.2.4 2002/05/01 08:34:37 alfred Exp $
  28  *      $DragonFly: src/sys/net/accf_http/accf_http.c,v 1.4 2007/04/22 01:13:13 dillon Exp $
  29  */
  30
  31 #define ACCEPT_FILTER_MOD
  32
  33 #include <sys/param.h>
  34 #include <sys/systm.h>
  35 #include <sys/sysproto.h>
  36 #include <sys/kernel.h>
  37 #include <sys/proc.h>
  38 #include <sys/malloc.h>
  39 #include <sys/unistd.h>
  40 #include <sys/file.h>
  41 #include <sys/fcntl.h>
  42 #include <sys/protosw.h>
  43 #include <sys/sysctl.h>
  44 #include <sys/socket.h>
  45 #include <sys/socketvar.h>
  46 #include <sys/stat.h>
  47 #include <sys/mbuf.h>
  48 #include <sys/resource.h>
  49 #include <sys/sysent.h>
  50 #include <sys/resourcevar.h>
  51
  52 /* check for GET/HEAD */
  53 static void sohashttpget(struct socket *so, void *arg, int waitflag);
  54 /* check for HTTP/1.0 or HTTP/1.1 */
  55 static void soparsehttpvers(struct socket *so, void *arg, int waitflag);
  56 /* check for end of HTTP/1.x request */
  57 static void soishttpconnected(struct socket *so, void *arg, int waitflag);
  58 /* strcmp on an mbuf chain */
  59 static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp);
  60 /* strncmp on an mbuf chain */
  61 static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset,
  62         int max, char *cmp);
  63 /* socketbuffer is full */
  64 static int sbfull(struct signalsockbuf *sb);
  65
  66 static struct accept_filter accf_http_filter = {
  67         "httpready",
  68         sohashttpget,
  69         NULL,
  70         NULL
  71 };
  72
  73 static moduledata_t accf_http_mod = {
  74         "accf_http",
  75         accept_filt_generic_mod_event,
  76         &accf_http_filter
  77 };
  78
  79 DECLARE_MODULE(accf_http, accf_http_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
  80
  81 static int parse_http_version = 1;
  82
  83 SYSCTL_NODE(_net_inet_accf, OID_AUTO, http, CTLFLAG_RW, 0,
  84 "HTTP accept filter");
  85 SYSCTL_INT(_net_inet_accf_http, OID_AUTO, parsehttpversion, CTLFLAG_RW,
  86 &parse_http_version, 1,
  87 "Parse http version so that non 1.x requests work");
  88
  89 #ifdef ACCF_HTTP_DEBUG
  90 #define DPRINT(fmt, args...) \
  91         do {    \
  92                 kprintf("%s:%d: " fmt "\n", __func__, __LINE__ , ##args);       \
  93         } while (0)
  94 #else
  95 #define DPRINT(fmt, args...)
  96 #endif
  97
  98 static int
  99 sbfull(struct signalsockbuf *ssb)
 100 {
 101
 102         DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, mbcnt(%ld) >= mbmax(%ld): %d",
 103             ssb->ssb_cc, ssb->ssb_hiwat, ssb->ssb_cc >= ssb->ssb_hiwat,
 104             ssb->ssb_mbcnt, ssb->ssb_mbmax, ssb->ssb_mbcnt >= ssb->ssb_mbmax);
 105         return(ssb->ssb_cc >= ssb->ssb_hiwat ||
 106                ssb->ssb_mbcnt >= ssb->ssb_mbmax);
 107 }
 108
 109 /*
 110  * start at mbuf m, (must provide npkt if exists)
 111  * starting at offset in m compare characters in mbuf chain for 'cmp'
 112  */
 113 static int
 114 mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp)
 115 {
 116         struct mbuf *n;
 117
 118         for (;m != NULL; m = n) {
 119                 n = npkt;
 120                 if (npkt)
 121                         npkt = npkt->m_nextpkt;
 122                 for (; m; m = m->m_next) {
 123                         for (; offset < m->m_len; offset++, cmp++) {
 124                                 if (*cmp == '\0') {
 125                                         return (1);
 126                                 } else if (*cmp != *(mtod(m, char *) + offset)) {
 127                                         return (0);
 128                                 }
 129                         }
 130                         if (*cmp == '\0')
 131                                 return (1);
 132                         offset = 0;
 133                 }
 134         }
 135         return (0);
 136 }
 137
 138 /*
 139  * start at mbuf m, (must provide npkt if exists)
 140  * starting at offset in m compare characters in mbuf chain for 'cmp'
 141  * stop at 'max' characters
 142  */
 143 static int
 144 mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int max, char *cmp)
 145 {
 146         struct mbuf *n;
 147
 148         for (;m != NULL; m = n) {
 149                 n = npkt;
 150                 if (npkt)
 151                         npkt = npkt->m_nextpkt;
 152                 for (; m; m = m->m_next) {
 153                         for (; offset < m->m_len; offset++, cmp++, max--) {
 154                                 if (max == 0 || *cmp == '\0') {
 155                                         return (1);
 156                                 } else if (*cmp != *(mtod(m, char *) + offset)) {
 157                                         return (0);
 158                                 }
 159                         }
 160                         if (max == 0 || *cmp == '\0')
 161                                 return (1);
 162                         offset = 0;
 163                 }
 164         }
 165         return (0);
 166 }
 167
 168 #define STRSETUP(sptr, slen, str) \
 169         do {    \
 170                 sptr = str;     \
 171                 slen = sizeof(str) - 1; \
 172         } while(0)
 173
 174 static void
 175 sohashttpget(struct socket *so, void *arg, int waitflag)
 176 {
 177
 178         if ((so->so_state & SS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) {
 179                 struct mbuf *m;
 180                 char *cmp;
 181                 int     cmplen, cc;
 182
 183                 m = so->so_rcv.ssb_mb;
 184                 cc = so->so_rcv.ssb_cc - 1;
 185                 if (cc < 1)
 186                         return;
 187                 switch (*mtod(m, char *)) {
 188                 case 'G':
 189                         STRSETUP(cmp, cmplen, "ET ");
 190                         break;
 191                 case 'H':
 192                         STRSETUP(cmp, cmplen, "EAD ");
 193                         break;
 194                 default:
 195                         goto fallout;
 196                 }
 197                 if (cc < cmplen) {
 198                         if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) {
 199                                 DPRINT("short cc (%d) but mbufstrncmp ok", cc);
 200                                 return;
 201                         } else {
 202                                 DPRINT("short cc (%d) mbufstrncmp failed", cc);
 203                                 goto fallout;
 204                         }
 205                 }
 206                 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) {
 207                         DPRINT("mbufstrcmp ok");
 208                         if (parse_http_version == 0)
 209                                 soishttpconnected(so, arg, waitflag);
 210                         else
 211                                 soparsehttpvers(so, arg, waitflag);
 212                         return;
 213                 }
 214                 DPRINT("mbufstrcmp bad");
 215         }
 216
 217 fallout:
 218         DPRINT("fallout");
 219         so->so_upcall = NULL;
 220         so->so_rcv.ssb_flags &= ~SSB_UPCALL;
 221         soisconnected(so);
 222         return;
 223 }
 224
 225 static void
 226 soparsehttpvers(struct socket *so, void *arg, int waitflag)
 227 {
 228         struct mbuf *m, *n;
 229         int     i, cc, spaces, inspaces;
 230
 231         if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
 232                 goto fallout;
 233
 234         m = so->so_rcv.ssb_mb;
 235         cc = so->so_rcv.ssb_cc;
 236         inspaces = spaces = 0;
 237         for (m = so->so_rcv.ssb_mb; m; m = n) {
 238                 n = m->m_nextpkt;
 239                 for (; m; m = m->m_next) {
 240                         for (i = 0; i < m->m_len; i++, cc--) {
 241                                 switch (*(mtod(m, char *) + i)) {
 242                                 case ' ':
 243                                         if (!inspaces) {
 244                                                 spaces++;
 245                                                 inspaces = 1;
 246                                         }
 247                                         break;
 248                                 case '\r':
 249                                 case '\n':
 250                                         DPRINT("newline");
 251                                         goto fallout;
 252                                 default:
 253                                         if (spaces == 2) {
 254                                                 /* make sure we have enough data left */
 255                                                 if (cc < sizeof("HTTP/1.0") - 1) {
 256                                                         if (mbufstrncmp(m, n, i, cc, "HTTP/1.") == 1) {
 257                                                                 DPRINT("mbufstrncmp ok");
 258                                                                 goto readmore;
 259                                                         } else {
 260                                                                 DPRINT("mbufstrncmp bad");
 261                                                                 goto fallout;
 262                                                         }
 263                                                 } else if (mbufstrcmp(m, n, i, "HTTP/1.0") == 1 ||
 264                                                                         mbufstrcmp(m, n, i, "HTTP/1.1") == 1) {
 265                                                                 DPRINT("mbufstrcmp ok");
 266                                                                 soishttpconnected(so, arg, waitflag);
 267                                                                 return;
 268                                                 } else {
 269                                                         DPRINT("mbufstrcmp bad");
 270                                                         goto fallout;
 271                                                 }
 272                                         }
 273                                         inspaces = 0;
 274                                         break;
 275                                 }
 276                         }
 277                 }
 278         }
 279 readmore:
 280         DPRINT("readmore");
 281         /*
 282          * if we hit here we haven't hit something
 283          * we don't understand or a newline, so try again
 284          */
 285         so->so_upcall = soparsehttpvers;
 286         so->so_rcv.ssb_flags |= SSB_UPCALL;
 287         return;
 288
 289 fallout:
 290         DPRINT("fallout");
 291         so->so_upcall = NULL;
 292         so->so_rcv.ssb_flags &= ~SSB_UPCALL;
 293         soisconnected(so);
 294         return;
 295 }
 296
 297
 298 #define NCHRS 3
 299
 300 static void
 301 soishttpconnected(struct socket *so, void *arg, int waitflag)
 302 {
 303         char a, b, c;
 304         struct mbuf *m, *n;
 305         int ccleft, copied;
 306
 307         DPRINT("start");
 308         if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
 309                 goto gotit;
 310
 311         /*
 312          * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c
 313          * copied - how much we've copied so far
 314          * ccleft - how many bytes remaining in the socketbuffer
 315          * just loop over the mbufs subtracting from 'ccleft' until we only
 316          * have NCHRS left
 317          */
 318         copied = 0;
 319         ccleft = so->so_rcv.ssb_cc;
 320         if (ccleft < NCHRS)
 321                 goto readmore;
 322         a = b = c = '\0';
 323         for (m = so->so_rcv.ssb_mb; m; m = n) {
 324                 n = m->m_nextpkt;
 325                 for (; m; m = m->m_next) {
 326                         ccleft -= m->m_len;
 327                         if (ccleft <= NCHRS) {
 328                                 char *src;
 329                                 int tocopy;
 330
 331                                 tocopy = (NCHRS - ccleft) - copied;
 332                                 src = mtod(m, char *) + (m->m_len - tocopy);
 333
 334                                 while (tocopy--) {
 335                                         switch (copied++) {
 336                                         case 0:
 337                                                 a = *src++;
 338                                                 break;
 339                                         case 1:
 340                                                 b = *src++;
 341                                                 break;
 342                                         case 2:
 343                                                 c = *src++;
 344                                                 break;
 345                                         }
 346                                 }
 347                         }
 348                 }
 349         }
 350         if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) {
 351                 /* we have all request headers */
 352                 goto gotit;
 353         }
 354
 355 readmore:
 356         so->so_upcall = soishttpconnected;
 357         so->so_rcv.ssb_flags |= SSB_UPCALL;
 358         return;
 359
 360 gotit:
 361         so->so_upcall = NULL;
 362         so->so_rcv.ssb_flags &= ~SSB_UPCALL;
 363         soisconnected(so);
 364         return;
 365 }