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