| 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 | |