#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <unistd.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/select.h>

#include "xmalloc.h"
#include "die.h"
#include "sock.h"
#include "stun.h"

#define BINDING_REQUEST               0x0001
#define BINDING_RESPONSE              0x0101

#define MAPPED_ADDRESS                0x0001

#define TIMEOUT                       5000
#define REQUEST_LEN                   20

#define ID_COOKIE_FIELD               htonl(((int) 'a' << 24) + \
					    ((int) 'c' << 16) + \
					    ((int) 'd' <<  8) + \
					     (int) 'c')

struct stun_header {
	uint16_t type;
	uint16_t len;
	uint32_t magic_cookie;
	uint32_t transid[3];
};

struct stun_attrib {
	uint16_t type;
	uint16_t len;
	uint8_t *value;
};

struct stun_mapped_addr {
	uint8_t none;
	uint8_t family;
	uint16_t port;
	uint32_t ip;
};

static int stun_test(const char *server_ip, int server_port,
		     int tun_port)
{
	int ret, sock;
	uint8_t pkt[256];
	uint8_t rpkt[256];
	size_t len, off, max;
	struct in_addr in;
	struct timeval timeout;
	struct stun_header *hdr, *rhdr;
	struct stun_attrib *attr;
	struct stun_mapped_addr *addr;
	struct sockaddr_in saddr, daddr;
	fd_set fdset;

	if (!server_ip)
		return -EINVAL;

	sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (sock < 0)
		panic("Cannot obtain socket!\n");

	set_reuseaddr(sock);

	memset(&saddr, 0, sizeof(saddr));
	saddr.sin_family = PF_INET;
	saddr.sin_port = htons(tun_port);
	saddr.sin_addr.s_addr = INADDR_ANY;

	ret = bind(sock, (struct sockaddr *) &saddr, sizeof(saddr));
	if (ret)
		panic("Cannot bind udp socket!\n");

	len = REQUEST_LEN;
	hdr = (struct stun_header *) pkt;
	hdr->type = htons(BINDING_REQUEST);
	hdr->len = 0;
	hdr->magic_cookie = ID_COOKIE_FIELD;
	hdr->transid[0] = htonl(rand());
	hdr->transid[1] = htonl(rand());
	hdr->transid[2] = htonl(rand());

	daddr.sin_family = PF_INET;
	daddr.sin_port = htons(server_port);
	daddr.sin_addr.s_addr = inet_addr(server_ip);

	ret = sendto(sock, pkt, len, 0, (struct sockaddr *) &daddr,
		     sizeof(daddr));
	if (ret != len) {
		printf("Error sending request (%s)!\n", strerror(errno));
		goto close_error;
	}

	timeout.tv_sec = TIMEOUT / 1000;
	timeout.tv_usec = (TIMEOUT % 1000) * 1000;

	FD_ZERO(&fdset);
	FD_SET(sock, &fdset);

	ret = select(sock + 1, &fdset, NULL, NULL, &timeout);
	if (ret <= 0) {
		printf("STUN server timeout!\n");
		goto close_error;
	}

	memset(rpkt, 0, sizeof(rpkt));
	len = read(sock, rpkt, sizeof(rpkt));

	close(sock);

	if (len < REQUEST_LEN) {
		printf("Bad STUN response (%s)!\n", strerror(errno));
		return -EIO;
	}

	rhdr = (struct stun_header *) rpkt;
	if (ntohs(rhdr->type) != BINDING_RESPONSE) {
		printf("Wrong STUN response type!\n");
		return -EIO;
	}

	if (rhdr->len == 0) {
		printf("No attributes in STUN response!\n");
		return -EIO;
	}

	if (rhdr->magic_cookie != hdr->magic_cookie ||
	    rhdr->transid[0] != hdr->transid[0] ||
	    rhdr->transid[1] != hdr->transid[1] ||
	    rhdr->transid[2] != hdr->transid[2]) {
		printf("Got wrong STUN transaction id!\n");
		return -EIO;
	}

	off = REQUEST_LEN;
	max = ntohs(rhdr->len) + REQUEST_LEN;

	while (off + 8 < max) {
		attr = (struct stun_attrib *) (rpkt + off);
		if (ntohs(attr->type) != MAPPED_ADDRESS)
			goto next;

		addr = (struct stun_mapped_addr *) (rpkt + off + 4);
		if (addr->family != 0x1)
			break;

		in.s_addr = addr->ip;
		printf("Public mapping %s:%u!\n",
		       inet_ntoa(in), ntohs(addr->port));
		break;
next:
		off += 4;
		off += ntohs(attr->len);
	}

	return 0;
close_error:
	close(sock);
	return -EIO;
}

int print_stun_probe(char *server, int sport, int tport)
{
	char *address;
	struct hostent *hp;

	printf("STUN on %s:%u\n", server, sport);

	srand(time(NULL));
	hp = gethostbyname(server);
	if (!hp)
		return -EIO;
	address = inet_ntoa(*(struct in_addr *) hp->h_addr_list[0]);
	return stun_test(address, sport, tport);
}
a'>e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba</a> (<a href='/cgit.cgi/linux/net-next.git/patch/mm?id=e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/'>f63906f41699c8e38af9d12b063e2ceab0286ef2</a> /<a href='/cgit.cgi/linux/net-next.git/tree/mm'>mm</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/mm?id=e34bac726d27056081d0250c0e173e4b155aa340'>e34bac726d27056081d0250c0e173e4b155aa340</a> (<a href='/cgit.cgi/linux/net-next.git/diff/mm?id2=e34bac726d27056081d0250c0e173e4b155aa340'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/mm?id=868c97a846a73e937d835b09b8c885a69df50ec8'>868c97a846a73e937d835b09b8c885a69df50ec8</a> (<a href='/cgit.cgi/linux/net-next.git/diff/mm?id2=868c97a846a73e937d835b09b8c885a69df50ec8'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge tag 'docs-4.10' of git://git.lwn.net/linux<span class='decoration'><a class='deco' href='/cgit.cgi/linux/net-next.git/commit/mm?id=e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba'>HEAD</a><a class='branch-deco' href='/cgit.cgi/linux/net-next.git/log/mm'>master</a></span></div><div class='commit-msg'>Pull documentation update from Jonathan Corbet:
 "These are the documentation changes for 4.10.

  It's another busy cycle for the docs tree, as the sphinx conversion
  continues. Highlights include:

   - Further work on PDF output, which remains a bit of a pain but
     should be more solid now.

   - Five more DocBook template files converted to Sphinx. Only 27 to
     go... Lots of plain-text files have also been converted and
     integrated.

   - Images in binary formats have been replaced with more
     source-friendly versions.

   - Various bits of organizational work, including the renaming of
     various files discussed at the kernel summit.

   - New documentation for the device_link mechanism.

  ... and, of course, lots of typo fixes and small updates"

* tag 'docs-4.10' of git://git.lwn.net/linux: (193 commits)
  dma-buf: Extract dma-buf.rst
  Update Documentation/00-INDEX
  docs: 00-INDEX: document directories/files with no docs
  docs: 00-INDEX: remove non-existing entries
  docs: 00-INDEX: add missing entries for documentation files/dirs
  docs: 00-INDEX: consolidate process/ and admin-guide/ description
  scripts: add a script to check if Documentation/00-INDEX is sane
  Docs: change sh -&gt; awk in REPORTING-BUGS
  Documentation/core-api/device_link: Add initial documentation
  core-api: remove an unexpected unident
  ppc/idle: Add documentation for powersave=off
  Doc: Correct typo, "Introdution" =&gt; "Introduction"
  Documentation/atomic_ops.txt: convert to ReST markup
  Documentation/local_ops.txt: convert to ReST markup
  Documentation/assoc_array.txt: convert to ReST markup
  docs-rst: parse-headers.pl: cleanup the documentation
  docs-rst: fix media cleandocs target
  docs-rst: media/Makefile: reorganize the rules
  docs-rst: media: build SVG from graphviz files
  docs-rst: replace bayer.png by a SVG image
  ...
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/'>Diffstat</a> (limited to 'mm')</div><table summary='diffstat' class='diffstat'>