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tap: Clean up tap reset path

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In tap_handler() if we get an error on the tap device or socket, we use
tap_sock_init() to re-initialise it.  However, what we actually need for
this reset case has remarkably little in common with the case where we're
initialising for the first time:
    * Re-initialising the packet pools is unnecessary
    * The case of a passed in fd (--fd) isn't relevant
    * We don't even call this for pasta mode
    * We will never re-call tap_sock_unix_init() because we never clear
      fd_tap_listen

In fact the only thing we do in tap_sock_init() relevant to the reset case
is to remove the fd from the epoll and close it... which isn't used in the
first initialisation case.

So make a new tap_sock_reset() function just for this case, and simplify
tap_sock_init() slightly as being used only for the first time case.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2023-08-11 15:12:17 +10:00 committed by Stefano Brivio
parent b2bea0047d
commit 28877b0fcd
1 changed files with 29 additions and 23 deletions
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42
tap.c
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@ -1236,9 +1236,9 @@ void tap_sock_init(struct ctx *c)
tap6_l4[i].p = PACKET_INIT(pool_l4, UIO_MAXIOV, pkt_buf, sz);
}
if (c->fd_tap != -1) {
if (c->one_off) { /* Passed as --fd */
if (c->fd_tap != -1) { /* Passed as --fd */
struct epoll_event ev = { 0 };
ASSERT(c->one_off);
ev.data.fd = c->fd_tap;
ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
@ -1246,11 +1246,6 @@ void tap_sock_init(struct ctx *c)
return;
}
epoll_ctl(c->epollfd, EPOLL_CTL_DEL, c->fd_tap, NULL);
close(c->fd_tap);
c->fd_tap = -1;
}
if (c->mode == MODE_PASST) {
if (c->fd_tap_listen == -1)
tap_sock_unix_init(c);
@ -1259,6 +1254,26 @@ void tap_sock_init(struct ctx *c)
}
}
/**
* tap_sock_reset() - Handle closing or failure of connect AF_UNIX socket
* @c: Execution context
*/
static void tap_sock_reset(struct ctx *c)
{
if (c->one_off) {
info("Client closed connection, exiting");
exit(EXIT_SUCCESS);
}
if (c->mode == MODE_PASTA)
die("Error on tap device, exiting");
/* Close the connected socket, wait for a new connection */
epoll_ctl(c->epollfd, EPOLL_CTL_DEL, c->fd_tap, NULL);
close(c->fd_tap);
c->fd_tap = -1;
}
/**
* tap_handler() - Packet handler for AF_UNIX or tuntap file descriptor
* @c: Execution context
@ -1276,15 +1291,6 @@ void tap_handler(struct ctx *c, int fd, uint32_t events,
if ((c->mode == MODE_PASST && tap_handler_passt(c, now)) ||
(c->mode == MODE_PASTA && tap_handler_pasta(c, now)) ||
(events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR))) {
if (c->one_off) {
info("Client closed connection, exiting");
exit(EXIT_SUCCESS);
}
if (c->mode == MODE_PASTA)
die("Error on tap device, exiting");
tap_sock_init(c);
}
(events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR)))
tap_sock_reset(c);
}