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/* |
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vpn_tcp.C -- handle the tcp part of the protocol. |
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Copyright (C) 2003-2007 Marc Lehmann <gvpe@schmorp.de> |
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|
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This file is part of GVPE. |
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|
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GVPE is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with gvpe; if not, write to the Free Software |
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Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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|
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#include "config.h" |
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|
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#if ENABLE_TCP |
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|
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// tcp processing is extremely ugly, since the gvpe protocol is simply |
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// designed for unreliable datagram networks. tcp is implemented by |
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// multiplexing packets over tcp. errors are completely ignored, as we |
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// rely on the higher level layers to time out and reconnect. |
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|
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#include <cstring> |
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|
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#include <sys/types.h> |
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#include <sys/socket.h> |
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#include <sys/wait.h> |
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#include <sys/uio.h> |
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#include <errno.h> |
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#include <time.h> |
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#include <unistd.h> |
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#include <fcntl.h> |
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|
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#include <map> |
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|
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#include "netcompat.h" |
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|
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#include "vpn.h" |
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|
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#if ENABLE_HTTP_PROXY |
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# include "conf.h" |
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#endif |
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|
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struct tcp_connection; |
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|
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struct lt_sockinfo |
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{ |
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bool operator()(const sockinfo *a, const sockinfo *b) const |
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{ |
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return *a < *b; |
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} |
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}; |
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|
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struct tcp_si_map : public map<const sockinfo *, tcp_connection *, lt_sockinfo> |
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{ |
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void cleaner_cb (ev::timer &w, int revents); ev::timer cleaner; |
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|
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tcp_si_map () |
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{ |
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cleaner.set<tcp_si_map, &tcp_si_map::cleaner_cb> (this); |
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cleaner.start (::conf.keepalive / 2, ::conf.keepalive / 2); |
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} |
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|
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} tcp_si; |
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|
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struct tcp_connection : ev::io |
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{ |
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int tos; |
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tstamp last_activity; |
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const sockinfo si; |
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vpn &v; |
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bool active; // this connection has been actively established |
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enum { ERROR, IDLE, CONNECTING, CONNECTING_PROXY, ESTABLISHED } state; |
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|
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vpn_packet *r_pkt; |
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u32 r_len, r_ofs; |
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|
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vpn_packet *w_pkt; |
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u32 w_len, w_ofs; |
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|
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#if ENABLE_HTTP_PROXY |
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char *proxy_req; |
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int proxy_req_len; |
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#endif |
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|
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void tcpv4_ev (ev::io &w, int revents); |
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|
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bool send_packet (vpn_packet *pkt, int tos); |
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bool write_packet (); |
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|
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void error (); // abort conenction && cleanup |
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|
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operator tcp_si_map::value_type() |
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{ |
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return tcp_si_map::value_type (&si, this); |
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} |
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|
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tcp_connection (int fd_, const sockinfo &si_, vpn &v_); |
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~tcp_connection (); |
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}; |
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|
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void tcp_si_map::cleaner_cb (ev::timer &w, int revents) |
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{ |
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tstamp to = ev_now () - ::conf.keepalive - 30 - 60; |
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|
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for (iterator i = begin (); i != end(); ) |
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if (i->second->last_activity >= to) |
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++i; |
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else |
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{ |
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delete i->second; |
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erase (i); |
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i = begin (); |
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} |
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} |
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|
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void |
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vpn::tcpv4_ev (ev::io &w, int revents) |
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{ |
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if (revents & EV_READ) |
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{ |
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struct sockaddr_in sa; |
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socklen_t sa_len = sizeof (sa); |
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int len; |
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|
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int fd = accept (w.fd, (sockaddr *)&sa, &sa_len); |
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|
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if (fd >= 0) |
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{ |
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fcntl (fd, F_SETFL, O_NONBLOCK); |
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fcntl (fd, F_SETFD, FD_CLOEXEC); |
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|
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sockinfo si(sa, PROT_TCPv4); |
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|
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slog (L_DEBUG, _("%s: accepted tcp connection"), (const char *)si);//D |
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|
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tcp_connection *i = new tcp_connection (fd, si, *this); |
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tcp_si.insert (*i); |
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} |
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} |
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} |
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|
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bool |
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vpn::send_tcpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) |
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{ |
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tcp_si_map::iterator info = tcp_si.find (&si); |
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|
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tcp_connection *i; |
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|
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if (info == tcp_si.end ()) |
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{ |
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i = new tcp_connection (-1, si, *this); |
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tcp_si.insert (*i); |
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} |
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else |
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i = info->second; |
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|
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return i->send_packet (pkt, tos); |
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} |
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|
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bool |
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tcp_connection::write_packet () |
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{ |
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ssize_t len; |
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|
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if (w_ofs < 2) |
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{ |
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u16 plen = htons (w_pkt->len); |
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|
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iovec vec[2]; |
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//TODO: char* is the right type? hardly... |
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vec[0].iov_base = (char *)((u8 *)&plen) + w_ofs; |
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vec[0].iov_len = 2 - w_ofs; |
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vec[1].iov_base = (char *)&((*w_pkt)[0]); |
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vec[1].iov_len = w_len - 2; |
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|
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len = writev (fd, vec, 2); |
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} |
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else |
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len = write (fd, &((*w_pkt)[w_ofs - 2]), w_len); |
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|
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if (len > 0) |
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{ |
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w_ofs += len; |
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w_len -= len; |
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|
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return w_len == 0; |
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} |
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else if (len < 0 && (errno == EAGAIN || errno == EINTR)) |
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return false; |
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else |
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{ |
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error (); |
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return false; |
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} |
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} |
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|
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void |
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tcp_connection::tcpv4_ev (ev::io &w, int revents) |
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{ |
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last_activity = ev_now (); |
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|
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if (revents & EV_WRITE) |
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{ |
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if (state == CONNECTING) |
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{ |
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state = ESTABLISHED; |
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set (EV_READ); |
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#if ENABLE_HTTP_PROXY |
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if (::conf.proxy_host && ::conf.proxy_port) |
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{ |
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state = CONNECTING_PROXY; |
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|
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if (write (fd, proxy_req, proxy_req_len) == 0) |
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{ |
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error (); |
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return; |
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} |
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|
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free (proxy_req); proxy_req = 0; |
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} |
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#endif |
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} |
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else if (state == ESTABLISHED) |
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{ |
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if (w_pkt) |
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{ |
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if (write_packet ()) |
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{ |
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delete w_pkt; w_pkt = 0; |
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|
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set (EV_READ); |
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} |
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} |
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else |
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set (EV_READ); |
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} |
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else |
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set (EV_READ); |
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} |
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|
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if (revents & EV_READ) |
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{ |
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if (state == ESTABLISHED) |
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for (;;) |
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{ |
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if (!r_pkt) |
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{ |
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r_pkt = new vpn_packet; |
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r_ofs = 0; |
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r_len = 2; // header |
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} |
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|
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ssize_t len = read (fd, &((*r_pkt)[r_ofs < 2 ? r_ofs : r_ofs - 2]), r_len); |
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|
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if (len > 0) |
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{ |
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r_len -= len; |
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r_ofs += len; |
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|
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if (r_len == 0) |
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{ |
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if (r_ofs == 2) |
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{ |
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r_len = ntohs (*(u16 *)&((*r_pkt)[0])); |
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r_pkt->len = r_len; |
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|
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if (r_len > 0 && r_len < MAXSIZE) |
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continue; |
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} |
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else |
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{ |
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v.recv_vpn_packet (r_pkt, si); |
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delete r_pkt; |
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r_pkt = 0; |
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|
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continue; |
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} |
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} |
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else |
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break; |
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} |
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else if (len < 0 && (errno == EINTR || errno == EAGAIN)) |
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break; |
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|
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// len == 0 <-> EOF |
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error (); |
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break; |
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} |
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#if ENABLE_HTTP_PROXY |
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else if (state == CONNECTING_PROXY) |
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{ |
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fcntl (fd, F_SETFL, 0); |
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char r[1024]; |
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int i; |
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bool emptyline = false; |
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|
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// we do a blocking read of the response, to hell with it |
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for (i = 0; i < 1023; i++) |
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{ |
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int l = read (fd, &r[i], 1); |
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|
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if (l <= 0) |
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{ |
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error (); |
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return; |
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} |
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|
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if (r[i] == '\012') |
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{ |
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if (emptyline) |
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break; |
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else |
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emptyline = true; |
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} |
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else if (r[i] != '\015') |
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emptyline = false; |
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} |
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|
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fcntl (fd, F_SETFL, O_NONBLOCK); |
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|
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if (i < 12) |
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{ |
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slog (L_ERR, _("(%s): unable to do proxy-forwarding, short response"), |
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(const char *)si); |
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error (); |
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} |
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else if (r[0] != 'H' || r[1] != 'T' || r[2] != 'T' || r[3] != 'P' || r[4] != '/' |
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|| r[5] != '1' // http-major |
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|| r[9] != '2') // response |
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{ |
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slog (L_ERR, _("(%s): malformed or unexpected proxy response (%.12s)"), |
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(const char *)si, r); |
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error (); |
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} |
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else |
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state = ESTABLISHED; |
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} |
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#endif |
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} |
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} |
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|
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bool |
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tcp_connection::send_packet (vpn_packet *pkt, int tos) |
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{ |
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last_activity = ev_now (); |
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|
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if (state == IDLE) |
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{ |
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// woaw, the first lost packet ;) |
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fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP); |
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|
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if (fd >= 0) |
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{ |
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const sockinfo *csi = &si; |
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|
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#if ENABLE_HTTP_PROXY |
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sockinfo psi; |
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|
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if (::conf.proxy_host && ::conf.proxy_port) |
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{ |
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psi.set (::conf.proxy_host, ::conf.proxy_port, PROT_TCPv4); |
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|
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if (psi.valid ()) |
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{ |
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csi = ψ |
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|
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proxy_req_len = asprintf (&proxy_req, |
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"CONNECT %s:%d HTTP/1.0\015\012" |
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"%s%s%s" // optional proxy-auth |
| 379 |
"\015\012", |
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si.ntoa (), |
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ntohs (si.port), |
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::conf.proxy_auth ? "Proxy-Authorization: Basic " : "", |
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::conf.proxy_auth ? ::conf.proxy_auth : "", |
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::conf.proxy_auth ? "\015\012" : ""); |
| 385 |
|
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} |
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else |
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slog (L_ERR, _("unable to resolve http proxy hostname '%s', trying direct"), |
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::conf.proxy_host); |
| 390 |
} |
| 391 |
#endif |
| 392 |
|
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fcntl (fd, F_SETFL, O_NONBLOCK); |
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|
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if (connect (fd, csi->sav4 (), csi->salenv4 ()) >= 0 |
| 396 |
|| errno == EINPROGRESS) |
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{ |
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fcntl (fd, F_SETFL, O_NONBLOCK); |
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fcntl (fd, F_SETFD, FD_CLOEXEC); |
| 400 |
|
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state = CONNECTING; |
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start (fd, EV_WRITE); |
| 403 |
} |
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else |
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close (fd); |
| 406 |
} |
| 407 |
} |
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else if (state == ESTABLISHED) |
| 409 |
{ |
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// drop packet if the tcp write buffer is full. this *is* the |
| 411 |
// right thing to do, not using tcp *is* the right thing to do. |
| 412 |
if (!w_pkt) |
| 413 |
{ |
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// how this maps to the underlying tcp packets we don't know |
| 415 |
// and we don't care. at least we tried ;) |
| 416 |
#if defined(SOL_IP) && defined(IP_TOS) |
| 417 |
if (tos != this->tos) |
| 418 |
{ |
| 419 |
this->tos = tos; |
| 420 |
setsockopt (fd, SOL_IP, IP_TOS, &tos, sizeof tos); |
| 421 |
} |
| 422 |
#endif |
| 423 |
|
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w_pkt = pkt; |
| 425 |
w_ofs = 0; |
| 426 |
w_len = pkt->len + 2; // length + size header |
| 427 |
|
| 428 |
if (write_packet ()) |
| 429 |
w_pkt = 0; |
| 430 |
else |
| 431 |
{ |
| 432 |
w_pkt = new vpn_packet; |
| 433 |
w_pkt->set (*pkt); |
| 434 |
|
| 435 |
set (EV_READ | EV_WRITE); |
| 436 |
} |
| 437 |
} |
| 438 |
} |
| 439 |
|
| 440 |
return state != ERROR; |
| 441 |
} |
| 442 |
|
| 443 |
void tcp_connection::error () |
| 444 |
{ |
| 445 |
stop (); |
| 446 |
|
| 447 |
if (fd >= 0) |
| 448 |
{ |
| 449 |
close (fd); |
| 450 |
tos = -1; |
| 451 |
fd = -1; |
| 452 |
} |
| 453 |
|
| 454 |
delete r_pkt; r_pkt = 0; |
| 455 |
delete w_pkt; w_pkt = 0; |
| 456 |
#if ENABLE_HTTP_PROXY |
| 457 |
free (proxy_req); proxy_req = 0; |
| 458 |
#endif |
| 459 |
|
| 460 |
state = active ? IDLE : ERROR; |
| 461 |
} |
| 462 |
|
| 463 |
tcp_connection::tcp_connection (int fd_, const sockinfo &si_, vpn &v_) |
| 464 |
: v(v_), si(si_) |
| 465 |
{ |
| 466 |
set<tcp_connection, &tcp_connection::tcpv4_ev> (this); |
| 467 |
|
| 468 |
last_activity = ev_now (); |
| 469 |
r_pkt = 0; |
| 470 |
w_pkt = 0; |
| 471 |
tos = -1; |
| 472 |
fd = fd_; |
| 473 |
#if ENABLE_HTTP_PROXY |
| 474 |
proxy_req = 0; |
| 475 |
#endif |
| 476 |
|
| 477 |
if (fd < 0) |
| 478 |
{ |
| 479 |
active = true; |
| 480 |
state = IDLE; |
| 481 |
} |
| 482 |
else |
| 483 |
{ |
| 484 |
active = false; |
| 485 |
state = ESTABLISHED; |
| 486 |
start (fd, EV_READ); |
| 487 |
} |
| 488 |
} |
| 489 |
|
| 490 |
tcp_connection::~tcp_connection () |
| 491 |
{ |
| 492 |
error (); |
| 493 |
} |
| 494 |
|
| 495 |
#endif |
| 496 |
|
