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tap-vsockd: proxy between the hyper-v socket and the tap device

Browse Source 
Signed-off-by: David Scott <dave.scott@docker.com>
This commit is contained in:
David Scott 2016-05-12 17:10:32 +01:00
parent 853d17e04f
commit b45ac6d9a8
1 changed files with 88 additions and 39 deletions
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127
alpine/packages/tap-vsockd/tap-vsockd.c
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@ -96,12 +96,6 @@ void sockerr(const char *msg)
fprintf(stderr, "%s Error: %d. %s", msg, errno, strerror(errno));
}
/* Argument passed to Client send thread */
struct client_args {
SOCKET fd;
int tosend;
};
void negotiate(SOCKET fd, struct vif_info *vif)
{
/* Negotiate with com.docker.slirp */
@ -135,47 +129,102 @@ err:
exit(1);
}
/* Argument passed to proxy threads */
struct connection {
SOCKET fd; /* Hyper-V socket with vmnet protocol */
int tapfd; /* TAP device with ethernet frames */
struct vif_info vif; /* Contains VIF MAC, MTU etc, received from server */
};
static void* vmnet_to_tap(void *arg)
{
int length, n;
struct connection *connection = (struct connection*) arg;
uint8_t header[2];
uint8_t buffer[2048];
for (;;) {
if (really_read(connection->fd, &header[0], 2) == -1){
fprintf(stderr, "Failed to read a packet header from host\n");
exit(1);
}
length = (header[0] & 0xff) | ((header[1] & 0xff) << 8);
if (length > sizeof(buffer)) {
fprintf(stderr, "Received an over-large packet: %d > %ld\n", length, sizeof(buffer));
exit(1);
}
if (really_read(connection->fd, &buffer[0], length) == -1){
fprintf(stderr, "Failed to read packet contents from host\n");
exit(1);
}
n = write(connection->tapfd, &buffer[0], length);
if (n != length) {
fprintf(stderr, "Failed to write %d bytes to tap device (wrote %d)\n", length, n);
exit(1);
}
}
}
static void* tap_to_vmnet(void *arg)
{
int length;
struct connection *connection = (struct connection*) arg;
uint8_t header[2];
uint8_t buffer[2048];
for (;;) {
length = read(connection->tapfd, &buffer[0], sizeof(buffer));
if (length == -1) {
if (errno == ENXIO) {
fprintf(stderr, "tap device has gone down\n");
exit(0);
}
fprintf(stderr, "ignoring error %d\n", errno);
/* This is what mirage-net-unix does. Is it a good idea really? */
continue;
}
header[0] = (length >> 0) & 0xff;
header[1] = (length >> 8) & 0xff;
if (really_write(connection->fd, &header[0], 2) == -1){
fprintf(stderr, "Failed to write packet header\n");
exit(1);
}
if (really_write(connection->fd, &buffer[0], length) == -1) {
fprintf(stderr, "Failed to write packet body\n");
exit(1);
}
}
}
/* Handle a connection. Handshake with the com.docker.slirp process and start
* exchanging ethernet frames between the socket and the tap device.
*/
static void handle(SOCKET fd, int tapfd)
{
char recvbuf[SVR_BUF_LEN];
int recvbuflen = SVR_BUF_LEN;
int received;
int sent;
int res;
struct connection connection;
pthread_t v2t, t2v;
struct vif_info vif;
negotiate(fd, &vif);
connection.fd = fd;
connection.tapfd = tapfd;
negotiate(fd, &connection.vif);
for (;;) {
received = recv(fd, recvbuf, recvbuflen, 0);
if (received == 0) {
printf("Peer closed\n");
break;
} else if (received == SOCKET_ERROR) {
sockerr("recv()");
return;
}
/* No error, echo */
printf("RX: %d Bytes\n", received);
sent = 0;
while (sent < received) {
res = send(fd, recvbuf + sent, received - sent, 0);
if (sent == SOCKET_ERROR) {
sockerr("send()");
return;
}
printf("TX: %d Bytes\n", res);
sent += res;
}
if (pthread_create(&v2t, NULL, vmnet_to_tap, &connection) != 0){
fprintf(stderr, "Failed to create the vmnet_to_tap thread\n");
exit(1);
}
if (pthread_create(&t2v, NULL, tap_to_vmnet, &connection) != 0){
fprintf(stderr, "Failed to create the tap_to_vmnet thread\n");
exit(1);
}
if (pthread_join(v2t, NULL) != 0){
fprintf(stderr, "Failed to join the vmnet_to_tap thread\n");
exit(1);
}
if (pthread_join(t2v, NULL) != 0){
fprintf(stderr, "Failed to join the tap_to_vmnet thread\n");
exit(1);
}
/* Dummy read to wait till other end closes */
recv(fd, recvbuf, recvbuflen, 0);
}