X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/tripe/blobdiff_plain/53a941d3f97a50964587c6e9533b1e43e74a57a8..11ad66c29764521f87f0dd399a1e592147c7af36:/server/tun-slip.c diff --git a/server/tun-slip.c b/server/tun-slip.c index 2c99a81a..1c452955 100644 --- a/server/tun-slip.c +++ b/server/tun-slip.c @@ -9,19 +9,18 @@ * * This file is part of Trivial IP Encryption (TrIPE). * - * TrIPE is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. + * TrIPE is free software: you can redistribute it and/or modify it under + * the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 3 of the License, or (at your + * option) any later version. * - * TrIPE is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. + * TrIPE is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. * * You should have received a copy of the GNU General Public License - * along with TrIPE; if not, write to the Free Software Foundation, - * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * along with TrIPE. If not, see . */ /*----- Header files ------------------------------------------------------*/ @@ -50,7 +49,9 @@ struct tunnel { unsigned st; /* Current parser state */ # define ST_ESC 1u /* Last saw an escape character */ # define ST_BAD 2u /* This packet is malformed */ +# define ST_MASK 3u /* Mask for the above bits */ # define ST_EOF 4u /* File descriptor reported EOF */ +# define ST_BROKEN 8u /* Sending side is broken */ size_t n; /* Number of bytes used in buffer */ octet buf[PKBUFSZ]; /* Buffer for incoming data */ }; @@ -62,11 +63,6 @@ static const char *slipcmd; /* Script to make new interfaces */ /*----- Main code ---------------------------------------------------------*/ -#define SL_END 0xc0 -#define SL_ESC 0xdb -#define SL_ESCEND 0xdc -#define SL_ESCESC 0xdd - /* --- @t_read@ --- * * * Arguments: @int fd@ = file descriptor to read @@ -98,12 +94,13 @@ static void t_read(int fd, unsigned mode, void *v) #endif errno == EAGAIN) return; - a_warn("TUN", "%s", p_ifname(t->p), "read-error", "?ERRNO", A_END); + a_warn("TUN", "%s", p_ifname(t->p), "slip", + "read-error", "?ERRNO", A_END); return; } if (!n) { a_warn("TUN", "%s", p_ifname(t->p), "slip", "eof", A_END); - t->st = ST_EOF; + t->st = (t->st & ~ST_MASK) | ST_EOF; sel_rmfile(&t->f); return; } @@ -123,9 +120,10 @@ static void t_read(int fd, unsigned mode, void *v) case SL_END: if (st & ST_BAD) ; - else if (st & ST_ESC) + else if (st & ST_ESC) { a_warn("TUN", "%s", p_ifname(t->p), "slip", "escape-end", A_END); - else if (q == t->buf) { + st |= ST_BAD; + } else if (q == t->buf) { T( trace(T_TUNNEL, "tun-slip: empty packet"); ) } else { IF_TRACING(T_TUNNEL, { @@ -137,7 +135,7 @@ static void t_read(int fd, unsigned mode, void *v) p_tun(t->p, &b); } q = t->buf; - st &= ~(ST_ESC | ST_BAD); + st &= ~ST_MASK; break; case SL_ESC: if ((st & ST_ESC) && !(st & ST_BAD)) { @@ -248,9 +246,33 @@ whine: moan("bad slip interface list"); } +/* --- @t_broken@ --- * + * + * Arguments: @tunnel *t@ = pointer to the tunnel + * + * Returns: --- + * + * Use: Marks the tunnel as broken and reports an error. + */ + +static void t_broken(tunnel *t) +{ + if (errno == EINTR || +#if defined(EWOULDBLOCK) && EWOULDBLOCK != EAGAIN + errno == EWOULDBLOCK || +#endif + errno == EAGAIN) + return; + a_warn("TUN", "%s", p_ifname(t->p), "slip", + "write-error", "?ERRNO", A_END); + T( trace(T_TUNNEL, "tun-slip: marking tunnel broken"); ) + t->st |= ST_BROKEN; +} + /* --- @t_create@ --- * * * Arguments: @peer *p@ = pointer to peer block + * @int fd@ = file descriptor of tunnel device (unused) * @char **ifn@ = where to put the interface name * * Returns: A tunnel block if it worked, or null on failure. @@ -258,15 +280,16 @@ whine: * Use: Initializes a new tunnel. */ -static tunnel *t_create(peer *p, char **ifn) +static tunnel *t_create(peer *p, int fd, char **ifn) { slipif *sl = 0; int pin[2] = { -1, -1 }, pout[2] = { -1, -1 }; + mdup_fd md[2]; pid_t kid = -1; dstr d = DSTR_INIT; unsigned char ch; tunnel *t; - static const char end[] = { SL_END, SL_END }; + static const octet end[] = { SL_END, SL_END }; /* --- Try to find a spare static interface --- */ @@ -296,10 +319,10 @@ static tunnel *t_create(peer *p, char **ifn) goto fail; } if (!kid) { - close(pin[1]); - close(pout[0]); - dup2(pin[0], STDIN_FILENO); - dup2(pout[1], STDOUT_FILENO); + close(pin[1]); close(pout[0]); + md[0].cur = pin[0]; md[0].want = STDIN_FILENO; + md[1].cur = pout[1]; md[1].want = STDOUT_FILENO; + mdup(md, 2); execlp(slipcmd, slipcmd, p_name(p), (char *)0); _exit(127); } @@ -343,7 +366,8 @@ found: sl->f |= F_INUSE; sel_initfile(&sel, &t->f, sl->ifd, SEL_READ, t_read, t); sel_addfile(&t->f); - write(sl->ofd, end, sizeof(end)); + if (write(sl->ofd, end, sizeof(end)) < 0) + t_broken(t); *ifn = xstrdup(sl->name); dstr_destroy(&d); return (t); @@ -395,6 +419,10 @@ static void t_inject(tunnel *t, buf *b) trace_block(T_PACKET, "tun-slip: packet contents", BBASE(b), BLEN(b)); }) + if (t-> st & ST_BROKEN) { + T( trace(T_TUNNEL, "tun-slip: tunnel broken; discarding"); ) + return; + } q = buf; *q++ = SL_END; for (p = BBASE(b), l = BCUR(b); p < l; p++) { @@ -409,7 +437,8 @@ static void t_inject(tunnel *t, buf *b) trace_block(T_PACKET, "tun-slip: SLIP-encapsulated contents", buf, q - buf); }) - write(t->sl->ofd, buf, q - buf); + if (write(t->sl->ofd, buf, q - buf) < 0) + t_broken(t); } /* --- @t_destroy@ --- * @@ -444,6 +473,7 @@ static void t_destroy(tunnel *t) const tunnel_ops tun_slip = { "slip", + 0, t_init, t_create, t_setifname,