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