1 /* $NetBSD: accf_http.c,v 1.9 2015/08/20 14:40:19 christos 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 1.9 2015/08/20 14:40:19 christos 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 #include "ioconf.h" 47 48 MODULE(MODULE_CLASS_MISC, accf_httpready, NULL); 49 50 /* check for GET/HEAD */ 51 static void sohashttpget(struct socket *so, void *arg, int events, int waitflag); 52 /* check for HTTP/1.0 or HTTP/1.1 */ 53 static void soparsehttpvers(struct socket *so, void *arg, int events, int waitflag); 54 /* check for end of HTTP/1.x request */ 55 static void soishttpconnected(struct socket *so, void *arg, int events, int waitflag); 56 /* strcmp on an mbuf chain */ 57 static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, const char *cmp); 58 /* strncmp on an mbuf chain */ 59 static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, 60 int len, const char *cmp); 61 /* socketbuffer is full */ 62 static int sbfull(struct sockbuf *sb); 63 64 static struct accept_filter accf_http_filter = { 65 .accf_name = "httpready", 66 .accf_callback = sohashttpget, 67 }; 68 69 /* 70 * Names of HTTP Accept filter sysctl objects 71 */ 72 73 #define ACCFCTL_PARSEVER 1 /* Parse HTTP version */ 74 75 static int parse_http_version = 1; 76 77 void 78 accf_httpattach(int junk) 79 { 80 81 } 82 83 static int 84 accf_httpready_modcmd(modcmd_t cmd, void *arg) 85 { 86 static struct sysctllog *clog; 87 int error; 88 89 switch (cmd) { 90 case MODULE_CMD_INIT: 91 error = accept_filt_add(&accf_http_filter); 92 if (error != 0) { 93 return error; 94 } 95 sysctl_createv(&clog, 0, NULL, NULL, 96 CTLFLAG_PERMANENT, 97 CTLTYPE_NODE, "inet", NULL, 98 NULL, 0, NULL, 0, 99 CTL_NET, PF_INET, CTL_EOL); 100 sysctl_createv(&clog, 0, NULL, NULL, 101 CTLFLAG_PERMANENT, 102 CTLTYPE_NODE, "accf", NULL, 103 NULL, 0, NULL, 0, 104 CTL_NET, PF_INET, SO_ACCEPTFILTER, CTL_EOL); 105 sysctl_createv(&clog, 0, NULL, NULL, 106 CTLFLAG_PERMANENT, 107 CTLTYPE_NODE, "http", 108 SYSCTL_DESCR("HTTP accept filter"), 109 NULL, 0, NULL, 0, 110 CTL_NET, PF_INET, SO_ACCEPTFILTER, ACCF_HTTP, CTL_EOL); 111 sysctl_createv(&clog, 0, NULL, NULL, 112 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 113 CTLTYPE_INT, "parsehttpversion", 114 SYSCTL_DESCR("Parse http version so that non " 115 "1.x requests work"), 116 NULL, 0, &parse_http_version, 0, 117 CTL_NET, PF_INET, SO_ACCEPTFILTER, ACCF_HTTP, 118 ACCFCTL_PARSEVER, CTL_EOL); 119 return 0; 120 121 case MODULE_CMD_FINI: 122 error = accept_filt_del(&accf_http_filter); 123 if (error != 0) { 124 return error; 125 } 126 sysctl_teardown(&clog); 127 return 0; 128 129 default: 130 return ENOTTY; 131 } 132 } 133 134 #ifdef ACCF_HTTP_DEBUG 135 #define DPRINT(fmt, args...) \ 136 do { \ 137 printf("%s:%d: " fmt "\n", __func__, __LINE__, ##args); \ 138 } while (0) 139 #else 140 #define DPRINT(fmt, args...) 141 #endif 142 143 static int 144 sbfull(struct sockbuf *sb) 145 { 146 147 DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, " 148 "mbcnt(%ld) >= mbmax(%ld): %d", 149 sb->sb_cc, sb->sb_hiwat, sb->sb_cc >= sb->sb_hiwat, 150 sb->sb_mbcnt, sb->sb_mbmax, sb->sb_mbcnt >= sb->sb_mbmax); 151 return (sb->sb_cc >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax); 152 } 153 154 /* 155 * start at mbuf m, (must provide npkt if exists) 156 * starting at offset in m compare characters in mbuf chain for 'cmp' 157 */ 158 static int 159 mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, const char *cmp) 160 { 161 struct mbuf *n; 162 163 for (; m != NULL; m = n) { 164 n = npkt; 165 if (npkt) 166 npkt = npkt->m_nextpkt; 167 for (; m; m = m->m_next) { 168 for (; offset < m->m_len; offset++, cmp++) { 169 if (*cmp == '\0') 170 return (1); 171 else if (*cmp != *(mtod(m, char *) + offset)) 172 return (0); 173 } 174 if (*cmp == '\0') 175 return (1); 176 offset = 0; 177 } 178 } 179 return (0); 180 } 181 182 /* 183 * start at mbuf m, (must provide npkt if exists) 184 * starting at offset in m compare characters in mbuf chain for 'cmp' 185 * stop at 'max' characters 186 */ 187 static int 188 mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int len, const char *cmp) 189 { 190 struct mbuf *n; 191 192 for (; m != NULL; m = n) { 193 n = npkt; 194 if (npkt) 195 npkt = npkt->m_nextpkt; 196 for (; m; m = m->m_next) { 197 for (; offset < m->m_len; offset++, cmp++, len--) { 198 if (len == 0 || *cmp == '\0') 199 return (1); 200 else if (*cmp != *(mtod(m, char *) + offset)) 201 return (0); 202 } 203 if (len == 0 || *cmp == '\0') 204 return (1); 205 offset = 0; 206 } 207 } 208 return (0); 209 } 210 211 #define STRSETUP(sptr, slen, str) \ 212 do { \ 213 sptr = str; \ 214 slen = sizeof(str) - 1; \ 215 } while(0) 216 217 static void 218 sohashttpget(struct socket *so, void *arg, int events, int waitflag) 219 { 220 221 if ((so->so_state & SS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) { 222 struct mbuf *m; 223 const char *cmp; 224 int cmplen, cc; 225 226 m = so->so_rcv.sb_mb; 227 cc = so->so_rcv.sb_cc - 1; 228 if (cc < 1) 229 return; 230 switch (*mtod(m, char *)) { 231 case 'G': 232 STRSETUP(cmp, cmplen, "ET "); 233 break; 234 case 'H': 235 STRSETUP(cmp, cmplen, "EAD "); 236 break; 237 default: 238 goto fallout; 239 } 240 if (cc < cmplen) { 241 if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) { 242 DPRINT("short cc (%d) but mbufstrncmp ok", cc); 243 return; 244 } else { 245 DPRINT("short cc (%d) mbufstrncmp failed", cc); 246 goto fallout; 247 } 248 } 249 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) { 250 DPRINT("mbufstrcmp ok"); 251 if (parse_http_version == 0) 252 soishttpconnected(so, arg, events, waitflag); 253 else 254 soparsehttpvers(so, arg, events, waitflag); 255 return; 256 } 257 DPRINT("mbufstrcmp bad"); 258 } 259 260 fallout: 261 DPRINT("fallout"); 262 so->so_upcall = NULL; 263 so->so_rcv.sb_flags &= ~SB_UPCALL; 264 soisconnected(so); 265 return; 266 } 267 268 static void 269 soparsehttpvers(struct socket *so, void *arg, int events, int waitflag) 270 { 271 struct mbuf *m, *n; 272 int i, cc, spaces, inspaces; 273 274 if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 275 goto fallout; 276 277 m = so->so_rcv.sb_mb; 278 cc = so->so_rcv.sb_cc; 279 inspaces = spaces = 0; 280 for (m = so->so_rcv.sb_mb; m; m = n) { 281 n = m->m_nextpkt; 282 for (; m; m = m->m_next) { 283 for (i = 0; i < m->m_len; i++, cc--) { 284 switch (*(mtod(m, char *) + i)) { 285 case ' ': 286 /* tabs? '\t' */ 287 if (!inspaces) { 288 spaces++; 289 inspaces = 1; 290 } 291 break; 292 case '\r': 293 case '\n': 294 DPRINT("newline"); 295 goto fallout; 296 default: 297 if (spaces != 2) { 298 inspaces = 0; 299 break; 300 } 301 302 /* 303 * if we don't have enough characters 304 * left (cc < sizeof("HTTP/1.0") - 1) 305 * then see if the remaining ones 306 * are a request we can parse. 307 */ 308 if (cc < sizeof("HTTP/1.0") - 1) { 309 if (mbufstrncmp(m, n, i, cc, 310 "HTTP/1.") == 1) { 311 DPRINT("ok"); 312 goto readmore; 313 } else { 314 DPRINT("bad"); 315 goto fallout; 316 } 317 } else if ( 318 mbufstrcmp(m, n, i, "HTTP/1.0") || 319 mbufstrcmp(m, n, i, "HTTP/1.1")) { 320 DPRINT("ok"); 321 soishttpconnected(so, 322 arg, events, waitflag); 323 return; 324 } else { 325 DPRINT("bad"); 326 goto fallout; 327 } 328 } 329 } 330 } 331 } 332 readmore: 333 DPRINT("readmore"); 334 /* 335 * if we hit here we haven't hit something 336 * we don't understand or a newline, so try again 337 */ 338 so->so_upcall = soparsehttpvers; 339 so->so_rcv.sb_flags |= SB_UPCALL; 340 return; 341 342 fallout: 343 DPRINT("fallout"); 344 so->so_upcall = NULL; 345 so->so_rcv.sb_flags &= ~SB_UPCALL; 346 soisconnected(so); 347 return; 348 } 349 350 351 #define NCHRS 3 352 353 static void 354 soishttpconnected(struct socket *so, void *arg, int events, int waitflag) 355 { 356 char a, b, c; 357 struct mbuf *m, *n; 358 int ccleft, copied; 359 360 DPRINT("start"); 361 if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 362 goto gotit; 363 364 /* 365 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c 366 * copied - how much we've copied so far 367 * ccleft - how many bytes remaining in the socketbuffer 368 * just loop over the mbufs subtracting from 'ccleft' until we only 369 * have NCHRS left 370 */ 371 copied = 0; 372 ccleft = so->so_rcv.sb_cc; 373 if (ccleft < NCHRS) 374 goto readmore; 375 a = b = c = '\0'; 376 for (m = so->so_rcv.sb_mb; m; m = n) { 377 n = m->m_nextpkt; 378 for (; m; m = m->m_next) { 379 ccleft -= m->m_len; 380 if (ccleft <= NCHRS) { 381 char *src; 382 int tocopy; 383 384 tocopy = (NCHRS - ccleft) - copied; 385 src = mtod(m, char *) + (m->m_len - tocopy); 386 387 while (tocopy--) { 388 switch (copied++) { 389 case 0: 390 a = *src++; 391 break; 392 case 1: 393 b = *src++; 394 break; 395 case 2: 396 c = *src++; 397 break; 398 } 399 } 400 } 401 } 402 } 403 if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) { 404 /* we have all request headers */ 405 goto gotit; 406 } 407 408 readmore: 409 so->so_upcall = soishttpconnected; 410 so->so_rcv.sb_flags |= SB_UPCALL; 411 return; 412 413 gotit: 414 so->so_upcall = NULL; 415 so->so_rcv.sb_flags &= ~SB_UPCALL; 416 soisconnected(so); 417 return; 418 } 419