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("$FreeBSD$"); 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 void sohashttpget(struct socket *so, void *arg, int waitflag); 43 /* check for HTTP/1.0 or HTTP/1.1 */ 44 static void soparsehttpvers(struct socket *so, void *arg, int waitflag); 45 /* check for end of HTTP/1.x request */ 46 static void 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 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 void 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; 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; 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 soishttpconnected(so, arg, waitflag); 197 else 198 soparsehttpvers(so, arg, waitflag); 199 return; 200 } 201 DPRINT("mbufstrcmp bad"); 202 } 203 204 fallout: 205 DPRINT("fallout"); 206 so->so_upcall = NULL; 207 so->so_rcv.sb_flags &= ~SB_UPCALL; 208 soisconnected(so); 209 return; 210 } 211 212 static void 213 soparsehttpvers(struct socket *so, void *arg, int waitflag) 214 { 215 struct mbuf *m, *n; 216 int i, cc, spaces, inspaces; 217 218 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 219 goto fallout; 220 221 m = so->so_rcv.sb_mb; 222 cc = so->so_rcv.sb_cc; 223 inspaces = spaces = 0; 224 for (m = so->so_rcv.sb_mb; m; m = n) { 225 n = m->m_nextpkt; 226 for (; m; m = m->m_next) { 227 for (i = 0; i < m->m_len; i++, cc--) { 228 switch (*(mtod(m, char *) + i)) { 229 case ' ': 230 /* tabs? '\t' */ 231 if (!inspaces) { 232 spaces++; 233 inspaces = 1; 234 } 235 break; 236 case '\r': 237 case '\n': 238 DPRINT("newline"); 239 goto fallout; 240 default: 241 if (spaces != 2) { 242 inspaces = 0; 243 break; 244 } 245 246 /* 247 * if we don't have enough characters 248 * left (cc < sizeof("HTTP/1.0") - 1) 249 * then see if the remaining ones 250 * are a request we can parse. 251 */ 252 if (cc < sizeof("HTTP/1.0") - 1) { 253 if (mbufstrncmp(m, n, i, cc, 254 "HTTP/1.") == 1) { 255 DPRINT("ok"); 256 goto readmore; 257 } else { 258 DPRINT("bad"); 259 goto fallout; 260 } 261 } else if ( 262 mbufstrcmp(m, n, i, "HTTP/1.0") || 263 mbufstrcmp(m, n, i, "HTTP/1.1")) { 264 DPRINT("ok"); 265 soishttpconnected(so, 266 arg, waitflag); 267 return; 268 } else { 269 DPRINT("bad"); 270 goto fallout; 271 } 272 } 273 } 274 } 275 } 276 readmore: 277 DPRINT("readmore"); 278 /* 279 * if we hit here we haven't hit something 280 * we don't understand or a newline, so try again 281 */ 282 so->so_upcall = soparsehttpvers; 283 so->so_rcv.sb_flags |= SB_UPCALL; 284 return; 285 286 fallout: 287 DPRINT("fallout"); 288 so->so_upcall = NULL; 289 so->so_rcv.sb_flags &= ~SB_UPCALL; 290 soisconnected(so); 291 return; 292 } 293 294 295 #define NCHRS 3 296 297 static void 298 soishttpconnected(struct socket *so, void *arg, int waitflag) 299 { 300 char a, b, c; 301 struct mbuf *m, *n; 302 int ccleft, copied; 303 304 DPRINT("start"); 305 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 306 goto gotit; 307 308 /* 309 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c 310 * copied - how much we've copied so far 311 * ccleft - how many bytes remaining in the socketbuffer 312 * just loop over the mbufs subtracting from 'ccleft' until we only 313 * have NCHRS left 314 */ 315 copied = 0; 316 ccleft = so->so_rcv.sb_cc; 317 if (ccleft < NCHRS) 318 goto readmore; 319 a = b = c = '\0'; 320 for (m = so->so_rcv.sb_mb; m; m = n) { 321 n = m->m_nextpkt; 322 for (; m; m = m->m_next) { 323 ccleft -= m->m_len; 324 if (ccleft <= NCHRS) { 325 char *src; 326 int tocopy; 327 328 tocopy = (NCHRS - ccleft) - copied; 329 src = mtod(m, char *) + (m->m_len - tocopy); 330 331 while (tocopy--) { 332 switch (copied++) { 333 case 0: 334 a = *src++; 335 break; 336 case 1: 337 b = *src++; 338 break; 339 case 2: 340 c = *src++; 341 break; 342 } 343 } 344 } 345 } 346 } 347 if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) { 348 /* we have all request headers */ 349 goto gotit; 350 } 351 352 readmore: 353 so->so_upcall = soishttpconnected; 354 so->so_rcv.sb_flags |= SB_UPCALL; 355 return; 356 357 gotit: 358 so->so_upcall = NULL; 359 so->so_rcv.sb_flags &= ~SB_UPCALL; 360 soisconnected(so); 361 return; 362 } 363