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/* |
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vpn_tcp.C -- handle the tcp part of the protocol. |
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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/poll.h> |
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#include <sys/wait.h> |
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#include <netinet/in.h> |
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#include <sys/uio.h> |
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#include <arpa/inet.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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|
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#include <map> |
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#include <unistd.h> |
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#include <fcntl.h> |
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#include <sys/poll.h> |
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|
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#include "vpn.h" |
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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, 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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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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|
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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.at = NOW + 600; |
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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 & (POLLIN | POLLERR)) |
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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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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; |
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r_pkt = 0; |
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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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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 & (POLLERR | POLLHUP)) |
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error (); |
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else if (revents & POLLOUT && state == CONNECTING) |
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{ |
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state = ESTABLISHED; |
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set (POLLIN); |
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} |
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|
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else if (revents & POLLIN) |
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{ |
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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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|
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} |
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else if (len < 0 && (errno == EINTR || errno == EAGAIN)) |
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return; |
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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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} |
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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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fcntl (fd, F_SETFL, O_NONBLOCK); |
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|
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if (connect (fd, si.sav4 (), si.salenv4 ()) >= 0 |
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|| errno == EINPROGRESS) |
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{ |
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state = CONNECTING; |
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start (fd, POLLOUT); |
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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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// how this maps to the underlying tcp packet we don't know |
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// and we don't care. at least we tried ;) |
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setsockopt (fd, SOL_IP, IP_TOS, &tos, sizeof tos); |
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|
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// we use none of the advantages of tcp; if an error occurs, just drop |
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// (this happens when a tcp connection gets stuck, too, which might not be |
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// the wisest thing to do.. either drop packet (too late) or make sure |
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// it gets delivered) |
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u16 len = htons (pkt->len); |
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|
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iovec vec[2]; |
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vec[0].iov_base = &len; |
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vec[0].iov_len = sizeof len; |
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vec[1].iov_base = &((*pkt)[0]); |
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vec[1].iov_len = pkt->len; |
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|
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if (sizeof (u16) + pkt->len != writev (fd, vec, 2)) |
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error (); |
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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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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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fd = fd_; |
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|
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if (fd < 0) |
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{ |
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active = true; |
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state = IDLE; |
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} |
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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, POLLIN); |
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} |
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} |
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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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|
