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