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(a)gibson.dropbear.id.au>
---
tcp.c | 23 +++++++++--------------
util.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
util.h | 14 ++++++++++++++
3 files changed, 79 insertions(+), 14 deletions(-)
Changes since v2:
* Removed use of iprintf() helper function, use some macros instead.
* Use sizeof("literal") approach to simplify some things.
Changes since v1:
* More careful and documented reasoning about the size of the strings
needed for output.
* Some more complex logic to calling inet_ntop() into a temporary
buffer then copying it
diff --git a/tcp.c b/tcp.c
index 21d0af06..efbbc1c0 100644
--- a/tcp.c
+++ b/tcp.c
@@ -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);
}
diff --git a/util.c b/util.c
index 849fa7f6..d66d366a 100644
--- a/util.c
+++ b/util.c
@@ -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;
+}
diff --git a/util.h b/util.h
index 264423bb..c8a357e3 100644
--- a/util.h
+++ b/util.h
@@ -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
--
2.45.1