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 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 (sbused(sb) >= 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 && 166 !sbfull(&so->so_rcv)) { 167 struct mbuf *m; 168 char *cmp; 169 int cmplen, cc; 170 171 m = so->so_rcv.sb_mb; 172 cc = sbavail(&so->so_rcv) - 1; 173 if (cc < 1) 174 return (SU_OK); 175 switch (*mtod(m, char *)) { 176 case 'G': 177 STRSETUP(cmp, cmplen, "ET "); 178 break; 179 case 'H': 180 STRSETUP(cmp, cmplen, "EAD "); 181 break; 182 default: 183 goto fallout; 184 } 185 if (cc < cmplen) { 186 if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) { 187 DPRINT("short cc (%d) but mbufstrncmp ok", cc); 188 return (SU_OK); 189 } else { 190 DPRINT("short cc (%d) mbufstrncmp failed", cc); 191 goto fallout; 192 } 193 } 194 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) { 195 DPRINT("mbufstrcmp ok"); 196 if (parse_http_version == 0) 197 return (soishttpconnected(so, arg, waitflag)); 198 else 199 return (soparsehttpvers(so, arg, waitflag)); 200 } 201 DPRINT("mbufstrcmp bad"); 202 } 203 204 fallout: 205 DPRINT("fallout"); 206 return (SU_ISCONNECTED); 207 } 208 209 static int 210 soparsehttpvers(struct socket *so, void *arg, int waitflag) 211 { 212 struct mbuf *m, *n; 213 int i, cc, spaces, inspaces; 214 215 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 216 goto fallout; 217 218 m = so->so_rcv.sb_mb; 219 cc = sbavail(&so->so_rcv); 220 inspaces = spaces = 0; 221 for (m = so->so_rcv.sb_mb; m; m = n) { 222 n = m->m_nextpkt; 223 for (; m; m = m->m_next) { 224 for (i = 0; i < m->m_len; i++, cc--) { 225 switch (*(mtod(m, char *) + i)) { 226 case ' ': 227 /* tabs? '\t' */ 228 if (!inspaces) { 229 spaces++; 230 inspaces = 1; 231 } 232 break; 233 case '\r': 234 case '\n': 235 DPRINT("newline"); 236 goto fallout; 237 default: 238 if (spaces != 2) { 239 inspaces = 0; 240 break; 241 } 242 243 /* 244 * if we don't have enough characters 245 * left (cc < sizeof("HTTP/1.0") - 1) 246 * then see if the remaining ones 247 * are a request we can parse. 248 */ 249 if (cc < sizeof("HTTP/1.0") - 1) { 250 if (mbufstrncmp(m, n, i, cc, 251 "HTTP/1.") == 1) { 252 DPRINT("ok"); 253 goto readmore; 254 } else { 255 DPRINT("bad"); 256 goto fallout; 257 } 258 } else if ( 259 mbufstrcmp(m, n, i, "HTTP/1.0") || 260 mbufstrcmp(m, n, i, "HTTP/1.1")) { 261 DPRINT("ok"); 262 return (soishttpconnected(so, 263 arg, waitflag)); 264 } else { 265 DPRINT("bad"); 266 goto fallout; 267 } 268 } 269 } 270 } 271 } 272 readmore: 273 DPRINT("readmore"); 274 /* 275 * if we hit here we haven't hit something 276 * we don't understand or a newline, so try again 277 */ 278 soupcall_set(so, SO_RCV, soparsehttpvers, arg); 279 return (SU_OK); 280 281 fallout: 282 DPRINT("fallout"); 283 return (SU_ISCONNECTED); 284 } 285 286 287 #define NCHRS 3 288 289 static int 290 soishttpconnected(struct socket *so, void *arg, int waitflag) 291 { 292 char a, b, c; 293 struct mbuf *m, *n; 294 int ccleft, copied; 295 296 DPRINT("start"); 297 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 298 goto gotit; 299 300 /* 301 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c 302 * copied - how much we've copied so far 303 * ccleft - how many bytes remaining in the socketbuffer 304 * just loop over the mbufs subtracting from 'ccleft' until we only 305 * have NCHRS left 306 */ 307 copied = 0; 308 ccleft = sbavail(&so->so_rcv); 309 if (ccleft < NCHRS) 310 goto readmore; 311 a = b = c = '\0'; 312 for (m = so->so_rcv.sb_mb; m; m = n) { 313 n = m->m_nextpkt; 314 for (; m; m = m->m_next) { 315 ccleft -= m->m_len; 316 if (ccleft <= NCHRS) { 317 char *src; 318 int tocopy; 319 320 tocopy = (NCHRS - ccleft) - copied; 321 src = mtod(m, char *) + (m->m_len - tocopy); 322 323 while (tocopy--) { 324 switch (copied++) { 325 case 0: 326 a = *src++; 327 break; 328 case 1: 329 b = *src++; 330 break; 331 case 2: 332 c = *src++; 333 break; 334 } 335 } 336 } 337 } 338 } 339 if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) { 340 /* we have all request headers */ 341 goto gotit; 342 } 343 344 readmore: 345 soupcall_set(so, SO_RCV, soishttpconnected, arg); 346 return (SU_OK); 347 348 gotit: 349 return (SU_ISCONNECTED); 350 } 351