1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2000 Paycounter, Inc. 5 * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #define ACCEPT_FILTER_MOD 34 35 #include <sys/param.h> 36 #include <sys/kernel.h> 37 #include <sys/mbuf.h> 38 #include <sys/module.h> 39 #include <sys/signalvar.h> 40 #include <sys/sysctl.h> 41 #include <sys/socketvar.h> 42 43 /* check for GET/HEAD */ 44 static int sohashttpget(struct socket *so, void *arg, int waitflag); 45 /* check for HTTP/1.0 or HTTP/1.1 */ 46 static int soparsehttpvers(struct socket *so, void *arg, int waitflag); 47 /* check for end of HTTP/1.x request */ 48 static int soishttpconnected(struct socket *so, void *arg, int waitflag); 49 /* strcmp on an mbuf chain */ 50 static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp); 51 /* strncmp on an mbuf chain */ 52 static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, 53 int max, char *cmp); 54 /* socketbuffer is full */ 55 static int sbfull(struct sockbuf *sb); 56 57 static struct accept_filter accf_http_filter = { 58 "httpready", 59 sohashttpget, 60 NULL, 61 NULL 62 }; 63 64 static moduledata_t accf_http_mod = { 65 "accf_http", 66 accept_filt_generic_mod_event, 67 &accf_http_filter 68 }; 69 70 DECLARE_MODULE(accf_http, accf_http_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE); 71 72 static int parse_http_version = 1; 73 74 static SYSCTL_NODE(_net_inet_accf, OID_AUTO, http, CTLFLAG_RW, 0, 75 "HTTP accept filter"); 76 SYSCTL_INT(_net_inet_accf_http, OID_AUTO, parsehttpversion, CTLFLAG_RW, 77 &parse_http_version, 1, 78 "Parse http version so that non 1.x requests work"); 79 80 #ifdef ACCF_HTTP_DEBUG 81 #define DPRINT(fmt, args...) \ 82 do { \ 83 printf("%s:%d: " fmt "\n", __func__, __LINE__, ##args); \ 84 } while (0) 85 #else 86 #define DPRINT(fmt, args...) 87 #endif 88 89 static int 90 sbfull(struct sockbuf *sb) 91 { 92 93 DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, " 94 "mbcnt(%ld) >= mbmax(%ld): %d", 95 sb->sb_cc, sb->sb_hiwat, sb->sb_cc >= sb->sb_hiwat, 96 sb->sb_mbcnt, sb->sb_mbmax, sb->sb_mbcnt >= sb->sb_mbmax); 97 return (sbused(sb) >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax); 98 } 99 100 /* 101 * start at mbuf m, (must provide npkt if exists) 102 * starting at offset in m compare characters in mbuf chain for 'cmp' 103 */ 104 static int 105 mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp) 106 { 107 struct mbuf *n; 108 109 for (; m != NULL; m = n) { 110 n = npkt; 111 if (npkt) 112 npkt = npkt->m_nextpkt; 113 for (; m; m = m->m_next) { 114 for (; offset < m->m_len; offset++, cmp++) { 115 if (*cmp == '\0') 116 return (1); 117 else if (*cmp != *(mtod(m, char *) + offset)) 118 return (0); 119 } 120 if (*cmp == '\0') 121 return (1); 122 offset = 0; 123 } 124 } 125 return (0); 126 } 127 128 /* 129 * start at mbuf m, (must provide npkt if exists) 130 * starting at offset in m compare characters in mbuf chain for 'cmp' 131 * stop at 'max' characters 132 */ 133 static int 134 mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int max, char *cmp) 135 { 136 struct mbuf *n; 137 138 for (; m != NULL; m = n) { 139 n = npkt; 140 if (npkt) 141 npkt = npkt->m_nextpkt; 142 for (; m; m = m->m_next) { 143 for (; offset < m->m_len; offset++, cmp++, max--) { 144 if (max == 0 || *cmp == '\0') 145 return (1); 146 else if (*cmp != *(mtod(m, char *) + offset)) 147 return (0); 148 } 149 if (max == 0 || *cmp == '\0') 150 return (1); 151 offset = 0; 152 } 153 } 154 return (0); 155 } 156 157 #define STRSETUP(sptr, slen, str) \ 158 do { \ 159 sptr = str; \ 160 slen = sizeof(str) - 1; \ 161 } while(0) 162 163 static int 164 sohashttpget(struct socket *so, void *arg, int waitflag) 165 { 166 167 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0 && 168 !sbfull(&so->so_rcv)) { 169 struct mbuf *m; 170 char *cmp; 171 int cmplen, cc; 172 173 m = so->so_rcv.sb_mb; 174 cc = sbavail(&so->so_rcv) - 1; 175 if (cc < 1) 176 return (SU_OK); 177 switch (*mtod(m, char *)) { 178 case 'G': 179 STRSETUP(cmp, cmplen, "ET "); 180 break; 181 case 'H': 182 STRSETUP(cmp, cmplen, "EAD "); 183 break; 184 default: 185 goto fallout; 186 } 187 if (cc < cmplen) { 188 if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) { 189 DPRINT("short cc (%d) but mbufstrncmp ok", cc); 190 return (SU_OK); 191 } else { 192 DPRINT("short cc (%d) mbufstrncmp failed", cc); 193 goto fallout; 194 } 195 } 196 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) { 197 DPRINT("mbufstrcmp ok"); 198 if (parse_http_version == 0) 199 return (soishttpconnected(so, arg, waitflag)); 200 else 201 return (soparsehttpvers(so, arg, waitflag)); 202 } 203 DPRINT("mbufstrcmp bad"); 204 } 205 206 fallout: 207 DPRINT("fallout"); 208 return (SU_ISCONNECTED); 209 } 210 211 static int 212 soparsehttpvers(struct socket *so, void *arg, int waitflag) 213 { 214 struct mbuf *m, *n; 215 int i, cc, spaces, inspaces; 216 217 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 218 goto fallout; 219 220 m = so->so_rcv.sb_mb; 221 cc = sbavail(&so->so_rcv); 222 inspaces = spaces = 0; 223 for (m = so->so_rcv.sb_mb; m; m = n) { 224 n = m->m_nextpkt; 225 for (; m; m = m->m_next) { 226 for (i = 0; i < m->m_len; i++, cc--) { 227 switch (*(mtod(m, char *) + i)) { 228 case ' ': 229 /* tabs? '\t' */ 230 if (!inspaces) { 231 spaces++; 232 inspaces = 1; 233 } 234 break; 235 case '\r': 236 case '\n': 237 DPRINT("newline"); 238 goto fallout; 239 default: 240 if (spaces != 2) { 241 inspaces = 0; 242 break; 243 } 244 245 /* 246 * if we don't have enough characters 247 * left (cc < sizeof("HTTP/1.0") - 1) 248 * then see if the remaining ones 249 * are a request we can parse. 250 */ 251 if (cc < sizeof("HTTP/1.0") - 1) { 252 if (mbufstrncmp(m, n, i, cc, 253 "HTTP/1.") == 1) { 254 DPRINT("ok"); 255 goto readmore; 256 } else { 257 DPRINT("bad"); 258 goto fallout; 259 } 260 } else if ( 261 mbufstrcmp(m, n, i, "HTTP/1.0") || 262 mbufstrcmp(m, n, i, "HTTP/1.1")) { 263 DPRINT("ok"); 264 return (soishttpconnected(so, 265 arg, waitflag)); 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 soupcall_set(so, SO_RCV, soparsehttpvers, arg); 281 return (SU_OK); 282 283 fallout: 284 DPRINT("fallout"); 285 return (SU_ISCONNECTED); 286 } 287 288 289 #define NCHRS 3 290 291 static int 292 soishttpconnected(struct socket *so, void *arg, int waitflag) 293 { 294 char a, b, c; 295 struct mbuf *m, *n; 296 int ccleft, copied; 297 298 DPRINT("start"); 299 if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 300 goto gotit; 301 302 /* 303 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c 304 * copied - how much we've copied so far 305 * ccleft - how many bytes remaining in the socketbuffer 306 * just loop over the mbufs subtracting from 'ccleft' until we only 307 * have NCHRS left 308 */ 309 copied = 0; 310 ccleft = sbavail(&so->so_rcv); 311 if (ccleft < NCHRS) 312 goto readmore; 313 a = b = c = '\0'; 314 for (m = so->so_rcv.sb_mb; m; m = n) { 315 n = m->m_nextpkt; 316 for (; m; m = m->m_next) { 317 ccleft -= m->m_len; 318 if (ccleft <= NCHRS) { 319 char *src; 320 int tocopy; 321 322 tocopy = (NCHRS - ccleft) - copied; 323 src = mtod(m, char *) + (m->m_len - tocopy); 324 325 while (tocopy--) { 326 switch (copied++) { 327 case 0: 328 a = *src++; 329 break; 330 case 1: 331 b = *src++; 332 break; 333 case 2: 334 c = *src++; 335 break; 336 } 337 } 338 } 339 } 340 } 341 if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) { 342 /* we have all request headers */ 343 goto gotit; 344 } 345 346 readmore: 347 soupcall_set(so, SO_RCV, soishttpconnected, arg); 348 return (SU_OK); 349 350 gotit: 351 return (SU_ISCONNECTED); 352 } 353