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/* |
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vpn_tcp.C -- handle the tcp part of the protocol. |
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Copyright (C) 2003-2004 Marc Lehmann <pcg@goof.com> |
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|
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This program 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 this program; if not, write to the Free Software |
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Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 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 vpe 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 protocol 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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void cleaner_cb (time_watcher &w); time_watcher cleaner; |
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|
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tcp_si_map () |
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: cleaner(this, &tcp_si_map::cleaner_cb) |
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{ |
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cleaner.start (0); |
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} |
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} tcp_si; |
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|
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struct tcp_connection : io_watcher { |
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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 (io_watcher &w, short 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 (time_watcher &w) |
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{ |
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w.start (NOW + 600); |
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|
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tstamp to = 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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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 (io_watcher &w, short revents) |
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{ |
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if (revents & EVENT_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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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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fcntl (fd, F_SETFL, O_NONBLOCK); |
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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 (io_watcher &w, short revents) |
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{ |
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last_activity = NOW; |
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|
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if (revents & EVENT_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 (EVENT_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 (EVENT_READ); |
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} |
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} |
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else |
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set (EVENT_READ); |
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} |
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else |
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set (EVENT_READ); |
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} |
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|
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if (revents & EVENT_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 = 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 |
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"\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" : ""); |
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|
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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); |
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} |
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#endif |
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|
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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 |
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|| errno == EINPROGRESS) |
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{ |
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state = CONNECTING; |
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start (fd, EVENT_WRITE); |
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} |
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else |
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close (fd); |
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} |
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} |
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else if (state == ESTABLISHED) |
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{ |
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// drop packet if the tcp write buffer is full. this *is* the |
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// right thing to do, not using tcp *is* the right thing to do. |
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if (!w_pkt) |
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{ |
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// how this maps to the underlying tcp packets we don't know |
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// and we don't care. at least we tried ;) |
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#if defined(SOL_IP) && defined(IP_TOS) |
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setsockopt (fd, SOL_IP, IP_TOS, &tos, sizeof tos); |
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#endif |
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|
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w_pkt = pkt; |
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w_ofs = 0; |
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w_len = pkt->len + 2; // length + size header |
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|
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if (write_packet ()) |
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w_pkt = 0; |
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else |
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{ |
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w_pkt = new vpn_packet; |
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w_pkt->set (*pkt); |
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|
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set (EVENT_READ | EVENT_WRITE); |
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} |
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} |
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} |
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|
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return state != ERROR; |
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} |
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|
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void tcp_connection::error () |
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{ |
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if (fd >= 0) |
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{ |
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close (fd); |
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fd = -1; |
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} |
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|
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delete r_pkt; r_pkt = 0; |
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delete w_pkt; w_pkt = 0; |
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#if ENABLE_HTTP_PROXY |
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free (proxy_req); proxy_req = 0; |
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#endif |
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|
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stop (); |
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state = active ? IDLE : ERROR; |
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} |
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|
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tcp_connection::tcp_connection (int fd_, const sockinfo &si_, vpn &v_) |
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: v(v_), si(si_), io_watcher(this, &tcp_connection::tcpv4_ev) |
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{ |
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last_activity = NOW; |
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r_pkt = 0; |
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w_pkt = 0; |
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fd = fd_; |
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#if ENABLE_HTTP_PROXY |
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proxy_req = 0; |
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#endif |
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|
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if (fd < 0) |
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{ |
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active = true; |
| 462 |
state = IDLE; |
| 463 |
} |
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else |
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{ |
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active = false; |
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state = ESTABLISHED; |
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start (fd, EVENT_READ); |
| 469 |
} |
| 470 |
} |
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|
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tcp_connection::~tcp_connection () |
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{ |
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error (); |
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} |
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|
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#endif |
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|
