1 /* $NetBSD: accf_http.c,v 1.8 2014/02/25 18:30:12 pooka Exp $ */ 2 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 __KERNEL_RCSID(0, "$NetBSD: accf_http.c,v 1.8 2014/02/25 18:30:12 pooka Exp $"); 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/socket.h> 42 #include <sys/socketvar.h> 43 44 #include <netinet/accept_filter.h> 45 46 MODULE(MODULE_CLASS_MISC, accf_httpready, NULL); 47 48 /* check for GET/HEAD */ 49 static void sohashttpget(struct socket *so, void *arg, int events, int waitflag); 50 /* check for HTTP/1.0 or HTTP/1.1 */ 51 static void soparsehttpvers(struct socket *so, void *arg, int events, int waitflag); 52 /* check for end of HTTP/1.x request */ 53 static void soishttpconnected(struct socket *so, void *arg, int events, int waitflag); 54 /* strcmp on an mbuf chain */ 55 static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, const char *cmp); 56 /* strncmp on an mbuf chain */ 57 static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, 58 int len, const char *cmp); 59 /* socketbuffer is full */ 60 static int sbfull(struct sockbuf *sb); 61 62 static struct accept_filter accf_http_filter = { 63 .accf_name = "httpready", 64 .accf_callback = sohashttpget, 65 }; 66 67 /* 68 * Names of HTTP Accept filter sysctl objects 69 */ 70 71 #define ACCFCTL_PARSEVER 1 /* Parse HTTP version */ 72 73 static int parse_http_version = 1; 74 75 /* XXX pseudo-device */ 76 void accf_httpattach(int); 77 78 void 79 accf_httpattach(int junk) 80 { 81 82 } 83 84 static int 85 accf_httpready_modcmd(modcmd_t cmd, void *arg) 86 { 87 static struct sysctllog *clog; 88 int error; 89 90 switch (cmd) { 91 case MODULE_CMD_INIT: 92 error = accept_filt_add(&accf_http_filter); 93 if (error != 0) { 94 return error; 95 } 96 sysctl_createv(&clog, 0, NULL, NULL, 97 CTLFLAG_PERMANENT, 98 CTLTYPE_NODE, "inet", NULL, 99 NULL, 0, NULL, 0, 100 CTL_NET, PF_INET, CTL_EOL); 101 sysctl_createv(&clog, 0, NULL, NULL, 102 CTLFLAG_PERMANENT, 103 CTLTYPE_NODE, "accf", NULL, 104 NULL, 0, NULL, 0, 105 CTL_NET, PF_INET, SO_ACCEPTFILTER, CTL_EOL); 106 sysctl_createv(&clog, 0, NULL, NULL, 107 CTLFLAG_PERMANENT, 108 CTLTYPE_NODE, "http", 109 SYSCTL_DESCR("HTTP accept filter"), 110 NULL, 0, NULL, 0, 111 CTL_NET, PF_INET, SO_ACCEPTFILTER, ACCF_HTTP, CTL_EOL); 112 sysctl_createv(&clog, 0, NULL, NULL, 113 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 114 CTLTYPE_INT, "parsehttpversion", 115 SYSCTL_DESCR("Parse http version so that non " 116 "1.x requests work"), 117 NULL, 0, &parse_http_version, 0, 118 CTL_NET, PF_INET, SO_ACCEPTFILTER, ACCF_HTTP, 119 ACCFCTL_PARSEVER, CTL_EOL); 120 return 0; 121 122 case MODULE_CMD_FINI: 123 error = accept_filt_del(&accf_http_filter); 124 if (error != 0) { 125 return error; 126 } 127 sysctl_teardown(&clog); 128 return 0; 129 130 default: 131 return ENOTTY; 132 } 133 } 134 135 #ifdef ACCF_HTTP_DEBUG 136 #define DPRINT(fmt, args...) \ 137 do { \ 138 printf("%s:%d: " fmt "\n", __func__, __LINE__, ##args); \ 139 } while (0) 140 #else 141 #define DPRINT(fmt, args...) 142 #endif 143 144 static int 145 sbfull(struct sockbuf *sb) 146 { 147 148 DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, " 149 "mbcnt(%ld) >= mbmax(%ld): %d", 150 sb->sb_cc, sb->sb_hiwat, sb->sb_cc >= sb->sb_hiwat, 151 sb->sb_mbcnt, sb->sb_mbmax, sb->sb_mbcnt >= sb->sb_mbmax); 152 return (sb->sb_cc >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax); 153 } 154 155 /* 156 * start at mbuf m, (must provide npkt if exists) 157 * starting at offset in m compare characters in mbuf chain for 'cmp' 158 */ 159 static int 160 mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, const char *cmp) 161 { 162 struct mbuf *n; 163 164 for (; m != NULL; m = n) { 165 n = npkt; 166 if (npkt) 167 npkt = npkt->m_nextpkt; 168 for (; m; m = m->m_next) { 169 for (; offset < m->m_len; offset++, cmp++) { 170 if (*cmp == '\0') 171 return (1); 172 else if (*cmp != *(mtod(m, char *) + offset)) 173 return (0); 174 } 175 if (*cmp == '\0') 176 return (1); 177 offset = 0; 178 } 179 } 180 return (0); 181 } 182 183 /* 184 * start at mbuf m, (must provide npkt if exists) 185 * starting at offset in m compare characters in mbuf chain for 'cmp' 186 * stop at 'max' characters 187 */ 188 static int 189 mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int len, const char *cmp) 190 { 191 struct mbuf *n; 192 193 for (; m != NULL; m = n) { 194 n = npkt; 195 if (npkt) 196 npkt = npkt->m_nextpkt; 197 for (; m; m = m->m_next) { 198 for (; offset < m->m_len; offset++, cmp++, len--) { 199 if (len == 0 || *cmp == '\0') 200 return (1); 201 else if (*cmp != *(mtod(m, char *) + offset)) 202 return (0); 203 } 204 if (len == 0 || *cmp == '\0') 205 return (1); 206 offset = 0; 207 } 208 } 209 return (0); 210 } 211 212 #define STRSETUP(sptr, slen, str) \ 213 do { \ 214 sptr = str; \ 215 slen = sizeof(str) - 1; \ 216 } while(0) 217 218 static void 219 sohashttpget(struct socket *so, void *arg, int events, int waitflag) 220 { 221 222 if ((so->so_state & SS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) { 223 struct mbuf *m; 224 const char *cmp; 225 int cmplen, cc; 226 227 m = so->so_rcv.sb_mb; 228 cc = so->so_rcv.sb_cc - 1; 229 if (cc < 1) 230 return; 231 switch (*mtod(m, char *)) { 232 case 'G': 233 STRSETUP(cmp, cmplen, "ET "); 234 break; 235 case 'H': 236 STRSETUP(cmp, cmplen, "EAD "); 237 break; 238 default: 239 goto fallout; 240 } 241 if (cc < cmplen) { 242 if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) { 243 DPRINT("short cc (%d) but mbufstrncmp ok", cc); 244 return; 245 } else { 246 DPRINT("short cc (%d) mbufstrncmp failed", cc); 247 goto fallout; 248 } 249 } 250 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) { 251 DPRINT("mbufstrcmp ok"); 252 if (parse_http_version == 0) 253 soishttpconnected(so, arg, events, waitflag); 254 else 255 soparsehttpvers(so, arg, events, waitflag); 256 return; 257 } 258 DPRINT("mbufstrcmp bad"); 259 } 260 261 fallout: 262 DPRINT("fallout"); 263 so->so_upcall = NULL; 264 so->so_rcv.sb_flags &= ~SB_UPCALL; 265 soisconnected(so); 266 return; 267 } 268 269 static void 270 soparsehttpvers(struct socket *so, void *arg, int events, int waitflag) 271 { 272 struct mbuf *m, *n; 273 int i, cc, spaces, inspaces; 274 275 if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 276 goto fallout; 277 278 m = so->so_rcv.sb_mb; 279 cc = so->so_rcv.sb_cc; 280 inspaces = spaces = 0; 281 for (m = so->so_rcv.sb_mb; m; m = n) { 282 n = m->m_nextpkt; 283 for (; m; m = m->m_next) { 284 for (i = 0; i < m->m_len; i++, cc--) { 285 switch (*(mtod(m, char *) + i)) { 286 case ' ': 287 /* tabs? '\t' */ 288 if (!inspaces) { 289 spaces++; 290 inspaces = 1; 291 } 292 break; 293 case '\r': 294 case '\n': 295 DPRINT("newline"); 296 goto fallout; 297 default: 298 if (spaces != 2) { 299 inspaces = 0; 300 break; 301 } 302 303 /* 304 * if we don't have enough characters 305 * left (cc < sizeof("HTTP/1.0") - 1) 306 * then see if the remaining ones 307 * are a request we can parse. 308 */ 309 if (cc < sizeof("HTTP/1.0") - 1) { 310 if (mbufstrncmp(m, n, i, cc, 311 "HTTP/1.") == 1) { 312 DPRINT("ok"); 313 goto readmore; 314 } else { 315 DPRINT("bad"); 316 goto fallout; 317 } 318 } else if ( 319 mbufstrcmp(m, n, i, "HTTP/1.0") || 320 mbufstrcmp(m, n, i, "HTTP/1.1")) { 321 DPRINT("ok"); 322 soishttpconnected(so, 323 arg, events, waitflag); 324 return; 325 } else { 326 DPRINT("bad"); 327 goto fallout; 328 } 329 } 330 } 331 } 332 } 333 readmore: 334 DPRINT("readmore"); 335 /* 336 * if we hit here we haven't hit something 337 * we don't understand or a newline, so try again 338 */ 339 so->so_upcall = soparsehttpvers; 340 so->so_rcv.sb_flags |= SB_UPCALL; 341 return; 342 343 fallout: 344 DPRINT("fallout"); 345 so->so_upcall = NULL; 346 so->so_rcv.sb_flags &= ~SB_UPCALL; 347 soisconnected(so); 348 return; 349 } 350 351 352 #define NCHRS 3 353 354 static void 355 soishttpconnected(struct socket *so, void *arg, int events, int waitflag) 356 { 357 char a, b, c; 358 struct mbuf *m, *n; 359 int ccleft, copied; 360 361 DPRINT("start"); 362 if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 363 goto gotit; 364 365 /* 366 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c 367 * copied - how much we've copied so far 368 * ccleft - how many bytes remaining in the socketbuffer 369 * just loop over the mbufs subtracting from 'ccleft' until we only 370 * have NCHRS left 371 */ 372 copied = 0; 373 ccleft = so->so_rcv.sb_cc; 374 if (ccleft < NCHRS) 375 goto readmore; 376 a = b = c = '\0'; 377 for (m = so->so_rcv.sb_mb; m; m = n) { 378 n = m->m_nextpkt; 379 for (; m; m = m->m_next) { 380 ccleft -= m->m_len; 381 if (ccleft <= NCHRS) { 382 char *src; 383 int tocopy; 384 385 tocopy = (NCHRS - ccleft) - copied; 386 src = mtod(m, char *) + (m->m_len - tocopy); 387 388 while (tocopy--) { 389 switch (copied++) { 390 case 0: 391 a = *src++; 392 break; 393 case 1: 394 b = *src++; 395 break; 396 case 2: 397 c = *src++; 398 break; 399 } 400 } 401 } 402 } 403 } 404 if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) { 405 /* we have all request headers */ 406 goto gotit; 407 } 408 409 readmore: 410 so->so_upcall = soishttpconnected; 411 so->so_rcv.sb_flags |= SB_UPCALL; 412 return; 413 414 gotit: 415 so->so_upcall = NULL; 416 so->so_rcv.sb_flags &= ~SB_UPCALL; 417 soisconnected(so); 418 return; 419 } 420