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icmp: Dedicated functions for starting and closing ping sequences

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ICMP sockets are cleaned up on a timeout implemented in icmp_timer_one(),
and the logic to do that cleanup is open coded in that function.  Similarly
new sockets are opened when we discover we don't have an existing one in
icmp_tap_handler(), and again the logic is open-coded.

That's not the worst thing, but it's a bit cleaner to have dedicated
functions for the creation and destruction of ping sockets.  This will also
make things a bit easier for future changes we have in mind.

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 2024-01-16 16:16:18 +11:00 committed by Stefano Brivio
parent b6a4e20aa6
commit 322660b0b9
1 changed files with 67 additions and 35 deletions
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102
icmp.c
View file

@ -133,6 +133,70 @@ unexpected:
warn("%s: Unexpected packet on ping socket", pname);
}
/**
* icmp_ping_close() - Close and clean up a ping socket
* @c: Execution context
* @id_sock: Socket number and other info
*/
static void icmp_ping_close(const struct ctx *c, struct icmp_id_sock *id_sock)
{
epoll_ctl(c->epollfd, EPOLL_CTL_DEL, id_sock->sock, NULL);
close(id_sock->sock);
id_sock->sock = -1;
id_sock->seq = -1;
}
/**
* icmp_ping_new() - Prepare a new ping socket for a new id
* @c: Execution context
* @id_sock: Socket fd and other information
* @af: Address family, AF_INET or AF_INET6
* @id: ICMP id for the new socket
*
* Return: Newly opened ping socket fd, or -1 on failure
*/
static int icmp_ping_new(const struct ctx *c, struct icmp_id_sock *id_sock,
int af, uint16_t id)
{
uint8_t proto = af == AF_INET ? IPPROTO_ICMP : IPPROTO_ICMPV6;
const char *const pname = af == AF_INET ? "ICMP" : "ICMPv6";
union icmp_epoll_ref iref = { .id = id };
const void *bind_addr;
const char *bind_if;
int s;
if (af == AF_INET) {
bind_addr = &c->ip4.addr_out;
bind_if = c->ip4.ifname_out;
} else {
bind_addr = &c->ip6.addr_out;
bind_if = c->ip6.ifname_out;
}
s = sock_l4(c, af, proto, bind_addr, bind_if, 0, iref.u32);
if (s < 0) {
warn("Cannot open \"ping\" socket. You might need to:");
warn(" sysctl -w net.ipv4.ping_group_range=\"0 2147483647\"");
warn("...echo requests/replies will fail.");
goto cancel;
}
if (s > FD_REF_MAX)
goto cancel;
id_sock->sock = s;
debug("%s: new socket %i for echo ID %"PRIu16, pname, s, id);
return s;
cancel:
if (s >= 0)
close(s);
return -1;
}
/**
* icmp_tap_handler() - Handle packets from tap
* @c: Execution context
@ -149,7 +213,6 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, int af,
const void *saddr, const void *daddr,
const struct pool *p, const struct timespec *now)
{
uint8_t proto = af == AF_INET ? IPPROTO_ICMP : IPPROTO_ICMPV6;
const char *const pname = af == AF_INET ? "ICMP" : "ICMPv6";
union {
struct sockaddr sa;
@ -203,37 +266,9 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, int af,
ASSERT(0);
}
if ((s = id_sock->sock) < 0) {
union icmp_epoll_ref iref = { .id = id };
const void *bind_addr;
const char *bind_if;
if (af == AF_INET) {
bind_addr = &c->ip4.addr_out;
bind_if = c->ip4.ifname_out;
} else {
bind_addr = &c->ip6.addr_out;
bind_if = c->ip6.ifname_out;
}
s = sock_l4(c, af, proto, bind_addr, bind_if, 0, iref.u32);
if (s < 0) {
warn("Cannot open \"ping\" socket. You might need to:");
warn(" sysctl -w net.ipv4.ping_group_range=\"0 2147483647\"");
warn("...echo requests/replies will fail.");
if ((s = id_sock->sock) < 0)
if ((s = icmp_ping_new(c, id_sock, af, id)) < 0)
return 1;
}
if (s > FD_REF_MAX) {
close(s);
return 1;
}
id_sock->sock = s;
debug("%s: new socket %i for echo ID %"PRIu16, pname, s, id);
}
id_sock->ts = now->tv_sec;
@ -260,10 +295,7 @@ static void icmp_timer_one(const struct ctx *c, struct icmp_id_sock *id_sock,
if (id_sock->sock < 0 || now->tv_sec - id_sock->ts <= ICMP_ECHO_TIMEOUT)
return;
epoll_ctl(c->epollfd, EPOLL_CTL_DEL, id_sock->sock, NULL);
close(id_sock->sock);
id_sock->sock = -1;
id_sock->seq = -1;
icmp_ping_close(c, id_sock);
}
/**