accf_http.c revision 95865
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: head/sys/netinet/accf_http.c 95865 2002-05-01 08:08:24Z alfred $ 28 */ 29 30#define ACCEPT_FILTER_MOD 31 32#include <sys/param.h> 33#include <sys/kernel.h> 34#include <sys/lock.h> 35#include <sys/mbuf.h> 36#include <sys/signalvar.h> 37#include <sys/sysctl.h> 38#include <sys/socketvar.h> 39#include <sys/sx.h> 40 41/* check for GET/HEAD */ 42static void sohashttpget(struct socket *so, void *arg, int waitflag); 43/* check for HTTP/1.0 or HTTP/1.1 */ 44static void soparsehttpvers(struct socket *so, void *arg, int waitflag); 45/* check for end of HTTP/1.x request */ 46static void soishttpconnected(struct socket *so, void *arg, int waitflag); 47/* strcmp on an mbuf chain */ 48static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp); 49/* strncmp on an mbuf chain */ 50static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, 51 int max, char *cmp); 52/* socketbuffer is full */ 53static int sbfull(struct sockbuf *sb); 54 55static struct accept_filter accf_http_filter = { 56 "httpready", 57 sohashttpget, 58 NULL, 59 NULL 60}; 61 62static moduledata_t accf_http_mod = { 63 "accf_http", 64 accept_filt_generic_mod_event, 65 &accf_http_filter 66}; 67 68DECLARE_MODULE(accf_http, accf_http_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE); 69 70static int parse_http_version = 1; 71 72SYSCTL_NODE(_net_inet_accf, OID_AUTO, http, CTLFLAG_RW, 0, 73"HTTP accept filter"); 74SYSCTL_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 87static int 88sbfull(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 (sb->sb_cc >= 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 */ 102static int 103mbufstrcmp(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 offset = 0; 119 } 120 } 121 return (0); 122} 123 124/* 125 * start at mbuf m, (must provide npkt if exists) 126 * starting at offset in m compare characters in mbuf chain for 'cmp' 127 * stop at 'max' characters 128 */ 129static int 130mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int max, char *cmp) 131{ 132 struct mbuf *n; 133 134 for (; m != NULL; m = n) { 135 n = npkt; 136 if (npkt) 137 npkt = npkt->m_nextpkt; 138 for (; m; m = m->m_next) { 139 for (; offset < m->m_len; offset++, cmp++, max--) { 140 if (max == 0 || *cmp == '\0') 141 return (1); 142 else if (*cmp != *(mtod(m, char *) + offset)) 143 return (0); 144 } 145 offset = 0; 146 } 147 } 148 return (0); 149} 150 151#define STRSETUP(sptr, slen, str) \ 152 do { \ 153 sptr = str; \ 154 slen = sizeof(str) - 1; \ 155 } while(0) 156 157static void 158sohashttpget(struct socket *so, void *arg, int waitflag) 159{ 160 161 if ((so->so_state & SS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) { 162 struct mbuf *m; 163 char *cmp; 164 int cmplen, cc; 165 166 m = so->so_rcv.sb_mb; 167 cc = so->so_rcv.sb_cc - 1; 168 if (cc < 1) 169 return; 170 switch (*mtod(m, char *)) { 171 case 'G': 172 STRSETUP(cmp, cmplen, "ET "); 173 break; 174 case 'H': 175 STRSETUP(cmp, cmplen, "EAD "); 176 break; 177 default: 178 goto fallout; 179 } 180 if (cc < cmplen) { 181 if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) { 182 DPRINT("short cc (%d) but mbufstrncmp ok", cc); 183 return; 184 } else { 185 DPRINT("short cc (%d) mbufstrncmp failed", cc); 186 goto fallout; 187 } 188 } 189 if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) { 190 DPRINT("mbufstrcmp ok"); 191 if (parse_http_version == 0) 192 soishttpconnected(so, arg, waitflag); 193 else 194 soparsehttpvers(so, arg, waitflag); 195 return; 196 } 197 DPRINT("mbufstrcmp bad"); 198 } 199 200fallout: 201 DPRINT("fallout"); 202 SIGIO_SLOCK(); 203 so->so_upcall = NULL; 204 so->so_rcv.sb_flags &= ~SB_UPCALL; 205 soisconnected_locked(so); 206 SIGIO_SUNLOCK(); 207 return; 208} 209 210static void 211soparsehttpvers(struct socket *so, void *arg, int waitflag) 212{ 213 struct mbuf *m, *n; 214 int i, cc, spaces, inspaces; 215 216 if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 217 goto fallout; 218 219 m = so->so_rcv.sb_mb; 220 cc = so->so_rcv.sb_cc; 221 inspaces = spaces = 0; 222 for (m = so->so_rcv.sb_mb; m; m = n) { 223 n = m->m_nextpkt; 224 for (; m; m = m->m_next) { 225 for (i = 0; i < m->m_len; i++, cc--) { 226 switch (*(mtod(m, char *) + i)) { 227 case ' ': 228 /* tabs? '\t' */ 229 if (!inspaces) { 230 spaces++; 231 inspaces = 1; 232 } 233 break; 234 case '\r': 235 case '\n': 236 DPRINT("newline"); 237 goto fallout; 238 default: 239 if (spaces != 2) { 240 inspaces = 0; 241 break; 242 } 243 244 /* 245 * if we don't have enough characters 246 * left (cc < sizeof("HTTP/1.0") - 1) 247 * then see if the remaining ones 248 * are a request we can parse. 249 */ 250 if (cc < sizeof("HTTP/1.0") - 1) { 251 if (mbufstrncmp(m, n, i, cc, 252 "HTTP/1.") == 1) { 253 DPRINT("ok"); 254 goto readmore; 255 } else { 256 DPRINT("bad"); 257 goto fallout; 258 } 259 } else if ( 260 mbufstrcmp(m, n, i, "HTTP/1.0") || 261 mbufstrcmp(m, n, i, "HTTP/1.1")) { 262 DPRINT("ok"); 263 soishttpconnected(so, 264 arg, waitflag); 265 return; 266 } else { 267 DPRINT("bad"); 268 goto fallout; 269 } 270 } 271 } 272 } 273 } 274readmore: 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 so->so_upcall = soparsehttpvers; 281 so->so_rcv.sb_flags |= SB_UPCALL; 282 return; 283 284fallout: 285 DPRINT("fallout"); 286 SIGIO_SLOCK(); 287 so->so_upcall = NULL; 288 so->so_rcv.sb_flags &= ~SB_UPCALL; 289 soisconnected_locked(so); 290 SIGIO_SUNLOCK(); 291 return; 292} 293 294 295#define NCHRS 3 296 297static void 298soishttpconnected(struct socket *so, void *arg, int waitflag) 299{ 300 char a, b, c; 301 struct mbuf *m, *n; 302 int ccleft, copied; 303 304 DPRINT("start"); 305 if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv)) 306 goto gotit; 307 308 /* 309 * Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c 310 * copied - how much we've copied so far 311 * ccleft - how many bytes remaining in the socketbuffer 312 * just loop over the mbufs subtracting from 'ccleft' until we only 313 * have NCHRS left 314 */ 315 copied = 0; 316 ccleft = so->so_rcv.sb_cc; 317 if (ccleft < NCHRS) 318 goto readmore; 319 a = b = c = '\0'; 320 for (m = so->so_rcv.sb_mb; m; m = n) { 321 n = m->m_nextpkt; 322 for (; m; m = m->m_next) { 323 ccleft -= m->m_len; 324 if (ccleft <= NCHRS) { 325 char *src; 326 int tocopy; 327 328 tocopy = (NCHRS - ccleft) - copied; 329 src = mtod(m, char *) + (m->m_len - tocopy); 330 331 while (tocopy--) { 332 switch (copied++) { 333 case 0: 334 a = *src++; 335 break; 336 case 1: 337 b = *src++; 338 break; 339 case 2: 340 c = *src++; 341 break; 342 } 343 } 344 } 345 } 346 } 347 if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) { 348 /* we have all request headers */ 349 goto gotit; 350 } 351 352readmore: 353 so->so_upcall = soishttpconnected; 354 so->so_rcv.sb_flags |= SB_UPCALL; 355 return; 356 357gotit: 358 SIGIO_SLOCK(); 359 so->so_upcall = NULL; 360 so->so_rcv.sb_flags &= ~SB_UPCALL; 361 soisconnected_locked(so); 362 SIGIO_SUNLOCK(); 363 return; 364} 365