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trezor-firmware/emulator/udp.c
2017-12-18 20:09:59 +01:00

86 lines
2.3 KiB
C

/*
* This file is part of the TREZOR project, https://trezor.io/
*
* Copyright (C) 2017 Saleem Rashid <trezor@saleemrashid.com>
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#define TREZOR_UDP_PORT 21324
static int fd = -1;
static struct sockaddr_in from;
static socklen_t fromlen;
void emulatorSocketInit(void) {
fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (fd < 0) {
perror("Failed to create socket");
exit(1);
}
fromlen = 0;
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(TREZOR_UDP_PORT);
addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) != 0) {
perror("Failed to bind socket");
exit(1);
}
}
size_t emulatorSocketRead(void *buffer, size_t size) {
fromlen = sizeof(from);
ssize_t n = recvfrom(fd, buffer, size, MSG_DONTWAIT, (struct sockaddr *) &from, &fromlen);
if (n < 0) {
if (errno != EAGAIN && errno != EWOULDBLOCK) {
perror("Failed to read socket");
}
return 0;
}
static const char msg_ping[] = { 'P', 'I', 'N', 'G', 'P', 'I', 'N', 'G' };
static const char msg_pong[] = { 'P', 'O', 'N', 'G', 'P', 'O', 'N', 'G' };
if (n == sizeof(msg_ping) && memcmp(buffer, msg_ping, sizeof(msg_ping)) == 0) {
emulatorSocketWrite(msg_pong, sizeof(msg_pong));
return 0;
}
return n;
}
size_t emulatorSocketWrite(const void *buffer, size_t size) {
if (fromlen > 0) {
ssize_t n = sendto(fd, buffer, size, MSG_DONTWAIT, (const struct sockaddr *) &from, fromlen);
if (n < 0 || ((size_t) n) != size) {
perror("Failed to write socket");
return 0;
}
}
return size;
}