--- /dev/null
+ GNU GENERAL PUBLIC LICENSE
+ Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
+ The licenses for most software are designed to take away your
+freedom to share and change it. By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users. This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it. (Some other Free Software Foundation software is covered by
+the GNU Lesser General Public License instead.) You can apply it to
+your programs, too.
+
+ When we speak of free software, we are referring to freedom, not
+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+ To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+ For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have. You must make sure that they, too, receive or can get the
+source code. And you must show them these terms so they know their
+rights.
+
+ We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+ Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software. If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+ Finally, any free program is threatened constantly by software
+patents. We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary. To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+ The precise terms and conditions for copying, distribution and
+modification follow.
+
+ GNU GENERAL PUBLIC LICENSE
+ TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+ 0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License. The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language. (Hereinafter, translation is included without limitation in
+the term "modification".) Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope. The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+ 1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+ 2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+ a) You must cause the modified files to carry prominent notices
+ stating that you changed the files and the date of any change.
+
+ b) You must cause any work that you distribute or publish, that in
+ whole or in part contains or is derived from the Program or any
+ part thereof, to be licensed as a whole at no charge to all third
+ parties under the terms of this License.
+
+ c) If the modified program normally reads commands interactively
+ when run, you must cause it, when started running for such
+ interactive use in the most ordinary way, to print or display an
+ announcement including an appropriate copyright notice and a
+ notice that there is no warranty (or else, saying that you provide
+ a warranty) and that users may redistribute the program under
+ these conditions, and telling the user how to view a copy of this
+ License. (Exception: if the Program itself is interactive but
+ does not normally print such an announcement, your work based on
+ the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole. If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works. But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+ 3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+ a) Accompany it with the complete corresponding machine-readable
+ source code, which must be distributed under the terms of Sections
+ 1 and 2 above on a medium customarily used for software interchange; or,
+
+ b) Accompany it with a written offer, valid for at least three
+ years, to give any third party, for a charge no more than your
+ cost of physically performing source distribution, a complete
+ machine-readable copy of the corresponding source code, to be
+ distributed under the terms of Sections 1 and 2 above on a medium
+ customarily used for software interchange; or,
+
+ c) Accompany it with the information you received as to the offer
+ to distribute corresponding source code. (This alternative is
+ allowed only for noncommercial distribution and only if you
+ received the program in object code or executable form with such
+ an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it. For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable. However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+ 4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License. Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+ 5. You are not required to accept this License, since you have not
+signed it. However, nothing else grants you permission to modify or
+distribute the Program or its derivative works. These actions are
+prohibited by law if you do not accept this License. Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+ 6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions. You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+ 7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License. If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all. For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices. Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+ 8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded. In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+ 9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time. Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number. If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation. If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+ 10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission. For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this. Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+ NO WARRANTY
+
+ 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+ 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+ <one line to give the program's name and a brief idea of what it does.>
+ Copyright (C) <year> <name of author>
+
+ This program 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.
+
+ This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+ Gnomovision version 69, Copyright (C) year name of author
+ Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary. Here is a sample; alter the names:
+
+ Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+ `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+ <signature of Ty Coon>, 1 April 1989
+ Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs. If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.
--- /dev/null
+CFLAGS ?= -O0 -Wall -g
+CFLAGS += -std=c99
+
+test: utcp.c test.c
+
+selftest: utcp.c selftest.c
+
+clean:
+ rm -f *.o test selftest
+
+.PHONY: clean
--- /dev/null
+This is a light-weight, user-space implementation of RFC 793 (TCP), without any
+reliance on an IP layer. It can be used to provide multiple in-order, reliable
+streams on top of any datagram layer.
+
+UTCP does not rely on a specific event system. Instead, the application feeds
+it with incoming packets using utcp_recv(), and outgoing data for the streams
+using utcp_send(). Most of the rest is handled by callbacks. The application
+must however call utcp_timeout() regularly to have UTCP handle packet loss.
+
+The application should run utcp_init() for every peer it wants to communicate
+with.
+
+DIFFERENCES FROM RFC 793:
+
+* No checksum. UTCP requires the application to handle packet integrity.
+* 32-bit window size. Big window sizes are the default.
+* No ECN, PSH, URG
+* Ports are a bit strange (for now).
+
+TODO v1.0:
+
+* Do ports the same way as real TCP?
+* Implement send buffer
+* Window scaling
+* Handle retransmission
+* Do proper modulo 2^32 comparisons of sequence numbers
+
+TODO v2.0:
+
+* Nagle
+* NAK and SACK
+* Congestion window scaling
+* Timestamps?
+
+Future ideas:
+
+Fast open:
+ SYN + data?
+
+Receive-only open:
+ SYN|FIN
+
+Fast transaction:
+ SYN|FIN + request data ->
+ <- SYN|ACK|FIN + response data
+ ACK ->
+
+Does this need special care or can we rely on higher level MACs?
--- /dev/null
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <errno.h>
+
+#include "utcp.h"
+
+struct utcp *a;
+struct utcp *b;
+struct utcp_connection *c;
+
+int do_recv(struct utcp_connection *x, void *data, size_t len) {
+ if(!len) {
+ if(errno)
+ fprintf(stderr, "%p Error: %s\n", x->utcp, strerror(errno));
+ else
+ fprintf(stderr, "%p Connection closed by peer\n", x->utcp);
+ if(x != c) {
+ fprintf(stderr, "closing my side too...\n");
+ utcp_close(x);
+ }
+ return -1;
+ }
+
+ if(x == c)
+ write(0, data, len);
+ else
+ utcp_send(x, data, len);
+
+ return 0;
+}
+
+bool do_pre_accept(struct utcp *utcp, void *data, size_t len) {
+ fprintf(stderr, "pre-accept\n");
+ if(len != 2 || strncmp(data, "oi", 2))
+ return false;
+ return true;
+}
+
+void do_accept(struct utcp_connection *c, void *data, size_t len) {
+ fprintf(stderr, "accept\n");
+ utcp_accept(c, do_recv, NULL);
+}
+
+int do_send(struct utcp *utcp, void *data, size_t len) {
+ static int count = 0;
+ if(++count > 1000) {
+ fprintf(stderr, "Too many packets!\n");
+ abort();
+ }
+
+ if(utcp == a)
+ return utcp_recv(b, data, len);
+ else
+ return utcp_recv(a, data, len);
+}
+
+
+int main(int argc, char *argv[]) {
+ srand(time(NULL));
+
+ a = utcp_init(do_accept, do_pre_accept, do_send, NULL);
+ b = utcp_init(NULL, NULL, do_send, NULL);
+
+ fprintf(stderr, "Testing connection to closed port\n\n");
+ c = utcp_connect(b, "zomg", 4, do_recv, NULL);
+
+ fprintf(stderr, "\nTesting conection to non-listening side\n\n");
+ c = utcp_connect(a, "oi", 2, do_recv, NULL);
+
+ fprintf(stderr, "\nTesting connection to open port, close\n\n");
+ c = utcp_connect(b, "oi", 2, do_recv, NULL);
+ fprintf(stderr, "closing...\n");
+ utcp_close(c);
+
+ fprintf(stderr, "\nTesting connection to open port, abort\n\n");
+ c = utcp_connect(b, "oi", 2, do_recv, NULL);
+ fprintf(stderr, "aborting...\n");
+ utcp_abort(c);
+
+ fprintf(stderr, "\nTesting connection with data transfer\n\n");
+
+ c = utcp_connect(b, "oi", 2, do_recv, NULL);
+ utcp_send(c, "Hello world!\n", 13);
+ utcp_send(c, "This is a test.\n", 16);
+ fprintf(stderr, "closing...\n");
+ utcp_close(c);
+
+ return 0;
+}
--- /dev/null
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <poll.h>
+
+
+#include "utcp.h"
+
+struct utcp_connection *c;
+int dir = 3;
+bool running = true;
+
+int do_recv(struct utcp_connection *c, void *data, size_t len) {
+ if(!data || !len) {
+ if(errno)
+ fprintf(stderr, "Error: %s\n", strerror(errno));
+ else {
+ dir &= ~2;
+ fprintf(stderr, "Connection closed by peer\n");
+ }
+ return 0;
+ }
+ return write(0, data, len);
+}
+
+void do_accept(struct utcp_connection *nc, void *data, size_t len) {
+ utcp_accept(nc, do_recv, NULL);
+ c = nc;
+}
+
+int do_send(struct utcp *utcp, void *data, size_t len) {
+ int s = *(int *)utcp->priv;
+ return send(s, data, len, MSG_DONTWAIT);
+}
+
+int main(int argc, char *argv[]) {
+ srand(time(NULL));
+
+ if(argc < 2 || argc > 3)
+ return 1;
+
+ bool server = argc == 2;
+ bool connected = false;
+
+ struct addrinfo *ai;
+ struct addrinfo hint = {
+ .ai_flags = server ? AI_PASSIVE : 0,
+ .ai_socktype = SOCK_DGRAM,
+ };
+
+ getaddrinfo(server ? NULL : argv[1], server ? argv[1] : argv[2], &hint, &ai);
+ if(!ai)
+ return 1;
+
+ int s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+ if(s < 0)
+ return 1;
+
+ if(server) {
+ if(bind(s, ai->ai_addr, ai->ai_addrlen))
+ return 1;
+ } else {
+ if(connect(s, ai->ai_addr, ai->ai_addrlen))
+ return 1;
+ connected = true;
+ }
+
+ struct utcp *u = utcp_init(server ? do_accept : NULL, NULL, do_send, &s);
+ if(!u)
+ return 1;
+
+ if(!server)
+ c = utcp_connect(u, "test", 4, do_recv, NULL);
+
+ struct pollfd fds[2] = {
+ {.fd = 0, .events = POLLIN | POLLERR | POLLHUP},
+ {.fd = s, .events = POLLIN | POLLERR | POLLHUP},
+ };
+
+ char buf[1024];
+
+ while(dir) {
+ int r = poll(fds, 2, 1000);
+ if(!r) {
+ utcp_timeout(u);
+ continue;
+ }
+
+ if(fds[0].revents) {
+ int len = read(0, buf, sizeof buf);
+ if(len <= 0) {
+ fds[0].fd = -1;
+ dir &= ~1;
+ if(c)
+ utcp_shutdown(c, SHUT_WR);
+ if(len < 0)
+ break;
+ else
+ continue;
+ }
+ if(c)
+ utcp_send(c, buf, len);
+ }
+
+ if(fds[1].revents) {
+ struct sockaddr_storage ss;
+ socklen_t sl;
+ int len = recvfrom(s, buf, sizeof buf, MSG_DONTWAIT, (struct sockaddr *)&ss, &sl);
+ if(len <= 0)
+ break;
+ if(!connected)
+ if(!connect(s, (struct sockaddr *)&ss, sl))
+ connected = true;
+ utcp_recv(u, buf, len);
+ }
+ };
+
+ utcp_close(c);
+ utcp_exit(u);
+
+ return 0;
+}
--- /dev/null
+/*
+ utcp.c -- Userspace TCP
+ Copyright (C) 2014 Guus Sliepen <guus@tinc-vpn.org>
+
+ This program 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.
+
+ This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+
+#define UTCP_INTERNAL
+#include "utcp.h"
+
+#define PREP(l) char pkt[(l) + sizeof struct hdr]; struct hdr *hdr = &pkt;
+
+#define SYN 1
+#define ACK 2
+#define FIN 4
+#define RST 8
+
+struct hdr {
+ uint16_t src; // Source port
+ uint16_t dst; // Destination port
+ uint32_t seq; // Sequence number
+ uint32_t ack; // Acknowledgement number
+ uint32_t wnd; // Window size
+ uint16_t ctl; // Flags (SYN, ACK, FIN, RST)
+ uint16_t aux; // other stuff
+};
+
+enum state {
+ CLOSED,
+ LISTEN,
+ SYN_SENT,
+ SYN_RECEIVED,
+ ESTABLISHED,
+ FIN_WAIT_1,
+ FIN_WAIT_2,
+ CLOSE_WAIT,
+ CLOSING,
+ LAST_ACK,
+ TIME_WAIT
+};
+
+const char *strstate[] = {
+ "CLOSED",
+ "LISTEN",
+ "SYN_SENT",
+ "SYN_RECEIVED",
+ "ESTABLISHED",
+ "FIN_WAIT_1",
+ "FIN_WAIT_2",
+ "CLOSE_WAIT",
+ "CLOSING",
+ "LAST_ACK",
+ "TIME_WAIT"
+};
+
+struct utcp_connection {
+ void *priv;
+ struct utcp *utcp;
+ bool reapable;
+
+ uint16_t src;
+ uint16_t dst;
+ enum state state;
+
+ // The following two structures form the TCB
+
+ struct {
+ uint32_t una;
+ uint32_t nxt;
+ uint32_t wnd;
+ uint32_t up;
+ uint32_t wl1;
+ uint32_t wl2;
+ uint32_t iss;
+ } snd;
+
+ struct {
+ uint32_t nxt;
+ uint32_t wnd;
+ uint32_t up;
+ uint32_t irs;
+ } rcv;
+
+ utcp_recv_t recv;
+
+ struct timeval conn_timeout;
+ struct timeval rtrx_timeout;
+};
+
+struct utcp {
+ void *priv;
+
+ utcp_accept_t accept;
+ utcp_pre_accept_t pre_accept;
+ utcp_send_t send;
+
+ uint16_t mtu;
+
+ struct utcp_connection **connections;
+ int nconnections;
+ int nallocated;
+ int gap;
+};
+
+static void set_state(struct utcp_connection *c, enum state state) {
+ c->state = state;
+ fprintf(stderr, "%p new state: %s\n", c->utcp, strstate[state]);
+}
+
+static void print_packet(void *pkt, size_t len) {
+ struct hdr hdr;
+ if(len < sizeof hdr) {
+ fprintf(stderr, "short packet (%zu bytes)\n", len);
+ return;
+ }
+
+ memcpy(&hdr, pkt, sizeof hdr);
+ fprintf (stderr, "src=%u dst=%u seq=%u ack=%u wnd=%u ctl=", hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd);
+ if(hdr.ctl & SYN)
+ fprintf(stderr, "SYN");
+ if(hdr.ctl & RST)
+ fprintf(stderr, "RST");
+ if(hdr.ctl & FIN)
+ fprintf(stderr, "FIN");
+ if(hdr.ctl & ACK)
+ fprintf(stderr, "ACK");
+
+ if(len > sizeof hdr) {
+ fprintf(stderr, " data=");
+ for(int i = sizeof hdr; i < len; i++) {
+ char *data = pkt;
+ fprintf(stderr, "%c", data[i] >= 32 ? data[i] : '.');
+ }
+ }
+
+ fprintf(stderr, "\n");
+}
+
+static struct utcp_connection *allocate_connection(struct utcp *utcp) {
+ struct utcp_connection *c;
+
+ // Initial allocation?
+
+ if(!utcp->nconnections) {
+ utcp->nallocated = 4;
+ utcp->nconnections = 1; // Skip 0
+ utcp->connections = calloc(utcp->nallocated, sizeof *utcp->connections);
+ }
+
+ // If there is a hole in the list of connections, use it.
+ // Otherwise, add a new connection to the end.
+
+ if(utcp->gap >= 0) {
+ c = utcp->connections[utcp->gap] = calloc(1, sizeof *c);
+ c->src = utcp->gap;
+ while(++utcp->gap < utcp->nconnections)
+ if(!utcp->connections[utcp->gap])
+ break;
+
+ if(utcp->gap >= utcp->nconnections)
+ utcp->gap = -1;
+ } else {
+ // Too many connections?
+
+ if(utcp->nconnections >= 65536) {
+ errno = ENOMEM;
+ return NULL;
+ }
+
+ // Need to reserve more memory?
+
+ if(utcp->nconnections >= utcp->nallocated) {
+ utcp->nallocated *= 2;
+ utcp->connections = realloc(utcp->connections, utcp->nallocated * sizeof *utcp->connections);
+ }
+
+ c = utcp->connections[utcp->nconnections] = calloc(1, sizeof *c);
+ c->src = utcp->nconnections++;
+ }
+
+ c->snd.iss = rand();
+ c->snd.una = c->snd.iss;
+ c->snd.nxt = c->snd.iss + 1;
+ c->rcv.wnd = utcp->mtu;
+ c->utcp = utcp;
+ return c;
+}
+
+static struct utcp_connection *find_connection(struct utcp *utcp, uint16_t src) {
+ if(src < utcp->nconnections && utcp->connections[src])
+ return utcp->connections[src];
+
+ errno = EINVAL;
+ return NULL;
+}
+
+static void free_connection(struct utcp_connection *c) {
+ if(!c)
+ return;
+ if(c->utcp->gap < 0 || c->src < c->utcp->gap)
+ c->utcp->gap = c->src;
+ c->utcp->connections[c->src] = NULL;
+ free(c);
+}
+
+struct utcp_connection *utcp_connect(struct utcp *utcp, void *data, size_t len, utcp_recv_t recv, void *priv) {
+ struct utcp_connection *c = allocate_connection(utcp);
+ if(!c)
+ return NULL;
+
+ c->recv = recv;
+
+ struct {
+ struct hdr hdr;
+ char data[len];
+ } pkt;
+
+ pkt.hdr.src = c->src;
+ pkt.hdr.dst = 0;
+ pkt.hdr.seq = c->snd.iss;
+ pkt.hdr.ack = 0;
+ pkt.hdr.ctl = SYN;
+ pkt.hdr.wnd = c->rcv.wnd;
+ memcpy(pkt.data, data, len);
+
+ set_state(c, SYN_SENT);
+
+ utcp->send(utcp, &pkt, sizeof pkt.hdr + len);
+
+ // Set timeout?
+
+ return c;
+}
+
+void utcp_accept(struct utcp_connection *c, utcp_recv_t recv, void *priv) {
+ if(c->reapable || c->state != SYN_RECEIVED) {
+ fprintf(stderr, "Error: accept() called on invalid connection %p in state %s\n", c, strstate[c->state]);
+ return;
+ }
+
+ fprintf(stderr, "%p accepted, %p %p\n", c, recv, priv);
+ c->recv = recv;
+ c->priv = priv;
+ set_state(c, ESTABLISHED);
+}
+
+int utcp_send(struct utcp_connection *c, void *data, size_t len) {
+ if(c->reapable) {
+ fprintf(stderr, "Error: send() called on closed connection %p\n", c);
+ errno = EBADF;
+ return -1;
+ }
+
+ switch(c->state) {
+ case CLOSED:
+ case LISTEN:
+ case SYN_SENT:
+ case SYN_RECEIVED:
+ fprintf(stderr, "Error: send() called on unconnected connection %p\n", c);
+ errno = ENOTCONN;
+ return -1;
+ case ESTABLISHED:
+ case CLOSE_WAIT:
+ break;
+ case FIN_WAIT_1:
+ case FIN_WAIT_2:
+ case CLOSING:
+ case LAST_ACK:
+ case TIME_WAIT:
+ fprintf(stderr, "Error: send() called on closing connection %p\n", c);
+ errno = EPIPE;
+ return -1;
+ }
+
+ struct {
+ struct hdr hdr;
+ char data[len];
+ } pkt;
+
+ pkt.hdr.src = c->src;
+ pkt.hdr.dst = c->dst;
+ pkt.hdr.seq = c->snd.nxt;
+ pkt.hdr.ack = c->rcv.nxt;
+ pkt.hdr.wnd = c->snd.wnd;
+ pkt.hdr.ctl = ACK;
+
+ memcpy(pkt.data, data, len);
+
+ c->snd.nxt += len;
+
+ c->utcp->send(c->utcp, &pkt, sizeof pkt.hdr + len);
+ //
+ // Can we add it to the send window?
+
+ // Do we need to kick some timers?
+
+ return 0;
+}
+
+static void swap_ports(struct hdr *hdr) {
+ uint16_t tmp = hdr->src;
+ hdr->src = hdr->dst;
+ hdr->dst = tmp;
+}
+
+int utcp_recv(struct utcp *utcp, void *data, size_t len) {
+ fprintf(stderr, "%p got: ", utcp);
+ print_packet(data, len);
+
+ struct hdr hdr;
+ if(len < sizeof hdr) {
+ errno = EBADMSG;
+ return -1;
+ }
+
+ memcpy(&hdr, data, sizeof hdr);
+ data += sizeof hdr;
+ len -= sizeof hdr;
+
+ if(hdr.ctl & ~(SYN | ACK | RST | FIN)) {
+ errno = EBADMSG;
+ return -1;
+ }
+
+ struct utcp_connection *c = find_connection(utcp, hdr.dst);
+
+ // Is it for a new connection?
+
+ if(!c) {
+ if(hdr.ctl & RST)
+ return 0;
+
+ if(hdr.ctl & SYN && !(hdr.ctl & ACK) && utcp->accept && (!utcp->pre_accept || utcp->pre_accept(utcp, data, len)) && (c = allocate_connection(utcp))) { // LISTEN
+ // Return SYN+ACK
+ c->snd.wnd = hdr.wnd;
+ c->rcv.irs = hdr.seq;
+ c->snd.iss = rand();
+ c->snd.una = c->snd.iss;
+ c->snd.nxt = c->snd.iss + 1;
+ c->rcv.nxt = c->rcv.irs + 1;
+ set_state(c, SYN_RECEIVED);
+
+ hdr.dst = c->dst = hdr.src;
+ hdr.src = c->src;
+ hdr.ack = c->rcv.irs + 1;
+ hdr.seq = c->snd.iss;
+ hdr.ctl = SYN | ACK;
+ utcp->send(utcp, &hdr, sizeof hdr);
+ return 0;
+ } else { // CLOSED
+ len = 1;
+ goto reset;
+ }
+ }
+
+ fprintf(stderr, "%p state %s\n", c->utcp, strstate[c->state]);
+
+ if(c->state == CLOSED) {
+ fprintf(stderr, "Error: packet recv()d on closed connection %p\n", c);
+ errno = EBADF;
+ return -1;
+ }
+
+ // It is for an existing connection.
+
+ if(c->state == SYN_SENT) {
+ if(hdr.ctl & ACK) {
+ if(hdr.ack <= c->snd.iss || hdr.ack > c->snd.nxt) {
+ fprintf(stderr, "Invalid ACK, %u %u %u\n", hdr.ack, c->snd.iss, c->snd.nxt);
+ goto reset;
+ }
+ }
+ if(hdr.ctl & RST) {
+ if(!(hdr.ctl & ACK))
+ return 0;
+ set_state(c, CLOSED);
+ errno = ECONNREFUSED;
+ c->recv(c, NULL, 0);
+ return 0;
+ }
+ if(hdr.ctl & SYN) {
+ c->dst = hdr.src;
+ c->rcv.nxt = hdr.seq + 1;
+ c->rcv.irs = hdr.seq;
+ c->snd.wnd = hdr.wnd;
+
+ if(hdr.ctl & ACK)
+ c->snd.una = hdr.ack;
+ if(c->snd.una > c->snd.iss) {
+ set_state(c, ESTABLISHED);
+ // TODO: signal app?
+ swap_ports(&hdr);
+ hdr.seq = c->snd.nxt;
+ hdr.ack = c->rcv.nxt;
+ hdr.ctl = ACK;
+ } else {
+ set_state(c, SYN_RECEIVED);
+ swap_ports(&hdr);
+ hdr.seq = c->snd.iss;
+ hdr.ack = c->rcv.nxt;
+ hdr.ctl = SYN | ACK;
+ }
+ utcp->send(utcp, &hdr, sizeof hdr);
+ // TODO: queue any data?
+ }
+
+ return 0;
+ }
+
+ bool acceptable;
+
+ if(len == 0)
+ if(c->rcv.wnd == 0)
+ acceptable = hdr.seq == c->rcv.nxt;
+ else
+ acceptable = (hdr.seq >= c->rcv.nxt && hdr.seq < c->rcv.nxt + c->rcv.wnd);
+ else
+ if(c->rcv.wnd == 0)
+ acceptable = false;
+ else
+ acceptable = (hdr.seq >= c->rcv.nxt && hdr.seq < c->rcv.nxt + c->rcv.wnd)
+ || (hdr.seq + len - 1 >= c->rcv.nxt && hdr.seq + len - 1 < c->rcv.nxt + c->rcv.wnd);
+
+ if(!acceptable) {
+ fprintf(stderr, "Packet not acceptable, %u %u %u %zu\n", hdr.seq, c->rcv.nxt, c->rcv.wnd, len);
+ if(hdr.ctl & RST)
+ return 0;
+ goto ack_and_drop;
+ }
+
+ c->snd.wnd = hdr.wnd;
+
+ // TODO: check whether segment really starts at rcv.nxt, otherwise trim it.
+
+ if(hdr.ctl & RST) {
+ switch(c->state) {
+ case SYN_RECEIVED:
+ // TODO: delete connection?
+ break;
+ case ESTABLISHED:
+ case FIN_WAIT_1:
+ case FIN_WAIT_2:
+ case CLOSE_WAIT:
+ set_state(c, CLOSED);
+ errno = ECONNRESET;
+ c->recv(c, NULL, 0);
+ break;
+ case CLOSING:
+ case LAST_ACK:
+ case TIME_WAIT:
+ // TODO: delete connection?
+ break;
+ default:
+ // TODO: wtf?
+ return 0;
+ }
+ set_state(c, CLOSED);
+ return 0;
+ }
+
+ if(hdr.ctl & SYN) {
+ switch(c->state) {
+ case SYN_RECEIVED:
+ case ESTABLISHED:
+ case FIN_WAIT_1:
+ case FIN_WAIT_2:
+ case CLOSE_WAIT:
+ case CLOSING:
+ case LAST_ACK:
+ case TIME_WAIT:
+ set_state(c, CLOSED);
+ errno = ECONNRESET;
+ c->recv(c, NULL, 0);
+ goto reset;
+ break;
+ default:
+ // TODO: wtf?
+ return 0;
+ }
+ }
+
+ if(!(hdr.ctl & ACK))
+ return 0;
+
+ switch(c->state) {
+ case SYN_RECEIVED:
+ if(hdr.ack >= c->snd.una && hdr.ack <= c->snd.nxt)
+ c->utcp->accept(c, NULL, 0);
+
+ if(c->state != ESTABLISHED)
+ goto reset;
+ break;
+ case ESTABLISHED:
+ case CLOSE_WAIT:
+ if(hdr.ack < c->snd.una)
+ return 0;
+ if(hdr.ack > c->snd.nxt)
+ goto ack_and_drop;
+ if(hdr.ack > c->snd.una && hdr.ack <= c->snd.nxt) {
+ c->snd.una = hdr.ack;
+ if(c->snd.wl1 < hdr.seq || (c->snd.wl1 == hdr.seq && c->snd.wl2 <= hdr.ack)) {
+ c->snd.wnd = hdr.wnd;
+ c->snd.wl1 = hdr.seq;
+ c->snd.wl2 = hdr.ack;
+ }
+ }
+ break;
+ case FIN_WAIT_1:
+ if(hdr.ack == c->snd.nxt)
+ set_state(c, FIN_WAIT_2);
+ break;
+ case FIN_WAIT_2:
+ // TODO: If nothing left to send, close.
+ break;
+ case CLOSING:
+ if(hdr.ack == c->snd.nxt) {
+ set_state(c, TIME_WAIT);
+ }
+ break;
+ case LAST_ACK:
+ if(hdr.ack == c->snd.nxt) {
+ set_state(c, CLOSED);
+ }
+ return 0;
+ case TIME_WAIT:
+ // TODO: retransmission of remote FIN, ACK and restart 2 MSL timeout
+ break;
+ default:
+ goto reset;
+ }
+
+ // Process data
+
+ switch(c->state) {
+ case ESTABLISHED:
+ case FIN_WAIT_1:
+ case FIN_WAIT_2:
+ // TODO: process the data, see page 74
+ break;
+ case CLOSE_WAIT:
+ case CLOSING:
+ case LAST_ACK:
+ case TIME_WAIT:
+ break;
+ default:
+ abort();
+ }
+
+ if(hdr.ctl & FIN) {
+ switch(c->state) {
+ case CLOSED:
+ case LISTEN:
+ case SYN_SENT:
+ return 0;
+ case SYN_RECEIVED:
+ case ESTABLISHED:
+ set_state(c, CLOSE_WAIT);
+ c->rcv.nxt++;
+ goto ack_and_drop;
+ case FIN_WAIT_1:
+ set_state(c, CLOSING);
+ c->rcv.nxt++;
+ goto ack_and_drop;
+ case FIN_WAIT_2:
+ set_state(c, TIME_WAIT);
+ c->rcv.nxt++;
+ goto ack_and_drop;
+ case CLOSE_WAIT:
+ case CLOSING:
+ case LAST_ACK:
+ case TIME_WAIT:
+ break;
+ default:
+ abort();
+ }
+ }
+
+ // Process the data
+
+ if(len && c->recv) {
+ c->recv(c, data, len);
+ c->rcv.nxt += len;
+ goto ack_and_drop;
+ }
+
+ return 0;
+
+reset:
+ swap_ports(&hdr);
+ hdr.wnd = 0;
+ if(hdr.ctl & ACK) {
+ hdr.seq = hdr.ack;
+ hdr.ctl = RST;
+ } else {
+ hdr.ack = hdr.seq + len;
+ hdr.seq = 0;
+ hdr.ctl = RST | ACK;
+ }
+ utcp->send(utcp, &hdr, sizeof hdr);
+ return 0;
+
+ack_and_drop:
+ swap_ports(&hdr);
+ hdr.seq = c->snd.nxt;
+ hdr.ack = c->rcv.nxt;
+ hdr.ctl = ACK;
+ utcp->send(utcp, &hdr, sizeof hdr);
+ if(c->state == CLOSE_WAIT || c->state == TIME_WAIT) {
+ errno = 0;
+ c->recv(c, NULL, 0);
+ }
+ return 0;
+}
+
+void utcp_shutdown(struct utcp_connection *c, int dir) {
+ if(c->reapable) {
+ fprintf(stderr, "Error: shutdown() called on closed connection %p\n", c);
+ return;
+ }
+
+ // TODO: handle dir
+
+ switch(c->state) {
+ case CLOSED:
+ return;
+ case LISTEN:
+ case SYN_SENT:
+ set_state(c, CLOSED);
+ return;
+
+ case SYN_RECEIVED:
+ case ESTABLISHED:
+ set_state(c, FIN_WAIT_1);
+ break;
+ case FIN_WAIT_1:
+ case FIN_WAIT_2:
+ return;
+ case CLOSE_WAIT:
+ set_state(c, LAST_ACK);
+ break;
+
+ case CLOSING:
+ case LAST_ACK:
+ case TIME_WAIT:
+ return;
+ }
+
+ // Send FIN
+
+ struct hdr hdr;
+
+ hdr.src = c->src;
+ hdr.dst = c->dst;
+ hdr.seq = c->snd.nxt;
+ hdr.ack = c->rcv.nxt;
+ hdr.wnd = c->snd.wnd;
+ hdr.ctl = FIN | ACK;
+
+ c->snd.nxt += 1;
+
+ c->utcp->send(c->utcp, &hdr, sizeof hdr);
+}
+
+void utcp_close(struct utcp_connection *c) {
+ utcp_shutdown(c, SHUT_RDWR);
+ c->reapable = true;
+}
+
+void utcp_abort(struct utcp_connection *c) {
+ if(c->reapable) {
+ fprintf(stderr, "Error: abort() called on closed connection %p\n", c);
+ return;
+ }
+
+ c->reapable = true;
+
+ switch(c->state) {
+ case CLOSED:
+ return;
+ case LISTEN:
+ case SYN_SENT:
+ case CLOSING:
+ case LAST_ACK:
+ case TIME_WAIT:
+ set_state(c, CLOSED);
+ return;
+
+ case SYN_RECEIVED:
+ case ESTABLISHED:
+ case FIN_WAIT_1:
+ case FIN_WAIT_2:
+ case CLOSE_WAIT:
+ set_state(c, CLOSED);
+ break;
+ }
+
+ // Send RST
+
+ struct hdr hdr;
+
+ hdr.src = c->src;
+ hdr.dst = c->dst;
+ hdr.seq = c->snd.nxt;
+ hdr.ack = 0;
+ hdr.wnd = 0;
+ hdr.ctl = RST;
+
+ c->utcp->send(c->utcp, &hdr, sizeof hdr);
+}
+
+void utcp_timeout(struct utcp *utcp) {
+ struct timeval now;
+ gettimeofday(&now, NULL);
+
+ for(int i = 0; i < utcp->nconnections; i++) {
+ struct utcp_connection *c = utcp->connections[i];
+ if(!c)
+ continue;
+
+ if(c->reapable) {
+ fprintf(stderr, "Reaping %p\n", c);
+ free_connection(c);
+ continue;
+ }
+
+ if(c->state == CLOSED)
+ return;
+
+ if(c->conn_timeout.tv_sec && timercmp(&c->conn_timeout, &now, <)) {
+ if(!c->reapable) {
+ errno = ETIMEDOUT;
+ c->recv(c, NULL, 0);
+ }
+ c->state = CLOSED;
+ return;
+ }
+
+ if(c->rtrx_timeout.tv_sec && timercmp(&c->rtrx_timeout, &now, <)) {
+ // TODO: retransmit stuff;
+ }
+ }
+}
+
+struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_send_t send, void *priv) {
+ struct utcp *utcp = calloc(1, sizeof *utcp);
+ if(!utcp)
+ return NULL;
+
+ utcp->accept = accept;
+ utcp->pre_accept = pre_accept;
+ utcp->send = send;
+ utcp->priv = priv;
+ utcp->gap = -1;
+ utcp->mtu = 1000;
+
+ return utcp;
+}
+
+void utcp_exit(struct utcp *utcp) {
+ if(!utcp)
+ return;
+ for(int i = 0; i < utcp->nconnections; i++)
+ free_connection(utcp->connections[i]);
+ free(utcp);
+}
--- /dev/null
+/*
+ utcp.h -- Userspace TCP
+ Copyright (C) 2014 Guus Sliepen <guus@tinc-vpn.org>
+
+ This program 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.
+
+ This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#ifndef UTCP_H
+#define UTCP_H
+
+#include <unistd.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifndef UTCP_INTERNAL
+struct utcp {
+ void *priv;
+};
+
+struct utcp_connection {
+ void *priv;
+ struct utcp *utcp;
+};
+#else
+struct utcp;
+struct utcp_connection;
+#endif
+
+typedef bool (*utcp_pre_accept_t)(struct utcp *utcp, void *data, size_t len);
+typedef void (*utcp_accept_t)(struct utcp_connection *utcp_connection, void *data, size_t len);
+
+typedef int (*utcp_send_t)(struct utcp *utcp, void *data, size_t len);
+typedef int (*utcp_recv_t)(struct utcp_connection *connection, void *data, size_t len);
+
+extern struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_send_t send, void *priv);
+extern void utcp_exit(struct utcp *utcp);
+extern struct utcp_connection *utcp_connect(struct utcp *utcp, void *data, size_t len, utcp_recv_t recv, void *priv);
+extern void utcp_accept(struct utcp_connection *utcp, utcp_recv_t recv, void *priv);
+extern int utcp_send(struct utcp_connection *connection, void *data, size_t len);
+extern int utcp_recv(struct utcp *utcp, void *data, size_t len);
+extern void utcp_close(struct utcp_connection *connection);
+extern void utcp_abort(struct utcp_connection *connection);
+extern void utcp_shutdown(struct utcp_connection *connection, int how);
+extern void utcp_timeout(struct utcp *utcp);
+
+#endif
projects / utcp / commitdiff