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util, tcp: Add helper to display socket addresses

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When reporting errors, we sometimes want to show a relevant socket address.
Doing so by extracting the various relevant fields can be pretty awkward,
so introduce a sockaddr_ntop() helper to make it simpler.  For now we just
have one user in tcp.c, but I have further upcoming patches which can make
use of it.

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 2024-05-21 14:48:03 +10:00 committed by Stefano Brivio
parent 3ff3a8a467
commit 1a20370b36
3 changed files with 79 additions and 14 deletions
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23
tcp.c
View file

@ -2758,6 +2758,7 @@ static void tcp_tap_conn_from_sock(struct ctx *c, in_port_t dstport,
void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
const struct timespec *now)
{
char sastr[SOCKADDR_STRLEN];
union sockaddr_inany sa;
socklen_t sl = sizeof(sa);
union flow *flow;
@ -2776,25 +2777,15 @@ void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
if (IN4_IS_ADDR_UNSPECIFIED(addr) ||
IN4_IS_ADDR_BROADCAST(addr) ||
IN4_IS_ADDR_MULTICAST(addr) || port == 0) {
char str[INET_ADDRSTRLEN];
err("Invalid endpoint from TCP accept(): %s:%hu",
inet_ntop(AF_INET, addr, str, sizeof(str)), port);
goto cancel;
}
IN4_IS_ADDR_MULTICAST(addr) || port == 0)
goto bad_endpoint;
} else if (sa.sa_family == AF_INET6) {
const struct in6_addr *addr = &sa.sa6.sin6_addr;
in_port_t port = sa.sa6.sin6_port;
if (IN6_IS_ADDR_UNSPECIFIED(addr) ||
IN6_IS_ADDR_MULTICAST(addr) || port == 0) {
char str[INET6_ADDRSTRLEN];
err("Invalid endpoint from TCP accept(): %s:%hu",
inet_ntop(AF_INET6, addr, str, sizeof(str)), port);
goto cancel;
}
IN6_IS_ADDR_MULTICAST(addr) || port == 0)
goto bad_endpoint;
}
if (tcp_splice_conn_from_sock(c, ref.tcp_listen.pif,
@ -2804,6 +2795,10 @@ void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
tcp_tap_conn_from_sock(c, ref.tcp_listen.port, flow, s, &sa, now);
return;
bad_endpoint:
err("Invalid endpoint from TCP accept(): %s",
sockaddr_ntop(&sa, sastr, sizeof(sastr)));
cancel:
flow_alloc_cancel(flow);
}

56
util.c
View file

@ -553,3 +553,59 @@ int write_remainder(int fd, const struct iovec *iov, int iovcnt, size_t skip)
return 0;
}
/** sockaddr_ntop() - Convert a socket address to text format
* @sa: Socket address
* @dst: output buffer, minimum SOCKADDR_STRLEN bytes
* @size: size of buffer at @dst
*
* Return: On success, a non-null pointer to @dst, NULL on failure
*/
const char *sockaddr_ntop(const void *sa, char *dst, socklen_t size)
{
sa_family_t family = ((const struct sockaddr *)sa)->sa_family;
socklen_t off = 0;
#define IPRINTF(...) \
do { \
off += snprintf(dst + off, size - off, __VA_ARGS__); \
if (off >= size) \
return NULL; \
} while (0)
#define INTOP(af, addr) \
do { \
if (!inet_ntop((af), (addr), dst + off, size - off)) \
return NULL; \
off += strlen(dst + off); \
} while (0)
switch (family) {
case AF_INET: {
const struct sockaddr_in *sa4 = sa;
INTOP(AF_INET, &sa4->sin_addr);
IPRINTF(":%hu", ntohs(sa4->sin_port));
break;
}
case AF_INET6: {
const struct sockaddr_in6 *sa6 = sa;
IPRINTF("[");
INTOP(AF_INET6, &sa6->sin6_addr);
IPRINTF("]:%hu", ntohs(sa6->sin6_port));
break;
}
/* FIXME: Implement AF_UNIX */
default:
errno = EAFNOSUPPORT;
return NULL;
}
#undef IPRINTF
#undef INTOP
return dst;
}

14
util.h
View file

@ -180,6 +180,20 @@ static inline const char *af_name(sa_family_t af)
}
}
#define UINT16_STRLEN (sizeof("65535"))
/* inet address (- '\0') + port (u16) (- '\0') + ':' + '\0' */
#define SOCKADDR_INET_STRLEN \
(INET_ADDRSTRLEN-1 + UINT16_STRLEN-1 + sizeof(":"))
/* inet6 address (- '\0') + port (u16) (- '\0') + '[' + ']' + ':' + '\0' */
#define SOCKADDR_INET6_STRLEN \
(INET6_ADDRSTRLEN-1 + UINT16_STRLEN-1 + sizeof("[]:"))
#define SOCKADDR_STRLEN MAX(SOCKADDR_INET_STRLEN, SOCKADDR_INET6_STRLEN)
const char *sockaddr_ntop(const void *sa, char *dst, socklen_t size);
/**
* mod_sub() - Modular arithmetic subtraction
* @a: Minued, unsigned value < @m