In the tcp_conn structure we have space for an IPv6 address, and use
IPv4-mapped IPv6 addresses to describe IPv4 connections. We open code
the construction of those IPv4-mapped address in two places.
Avoid the duplication with a helper function.
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
tcp.c | 9 ++-------
util.c | 20 ++++++++++++++++++++
util.h | 1 +
3 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/tcp.c b/tcp.c
index 3d48d6e..26dd268 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2217,9 +2217,7 @@ static void tcp_conn_from_tap(struct ctx *c, int af, const void
*addr,
sa = (struct sockaddr *)&addr4;
sl = sizeof(addr4);
- memset(&conn->a.a4.zero, 0, sizeof(conn->a.a4.zero));
- memset(&conn->a.a4.one, 0xff, sizeof(conn->a.a4.one));
- memcpy(&conn->a.a4.a, addr, sizeof(conn->a.a4.a));
+ encode_ip4mapped_ip6(&conn->a.a6, addr);
} else {
sa = (struct sockaddr *)&addr6;
sl = sizeof(addr6);
@@ -2902,15 +2900,12 @@ static void tcp_conn_from_sock(struct ctx *c, union epoll_ref
ref,
memcpy(&sa4, &sa, sizeof(sa4));
- memset(&conn->a.a4.zero, 0, sizeof(conn->a.a4.zero));
- memset(&conn->a.a4.one, 0xff, sizeof(conn->a.a4.one));
-
if (IN4_IS_ADDR_LOOPBACK(&sa4.sin_addr) ||
IN4_IS_ADDR_UNSPECIFIED(&sa4.sin_addr) ||
IN4_ARE_ADDR_EQUAL(&sa4.sin_addr, &c->ip4.addr_seen))
sa4.sin_addr = c->ip4.gw;
- conn->a.a4.a = sa4.sin_addr;
+ encode_ip4mapped_ip6(&conn->a.a6, &sa4.sin_addr);
conn->sock_port = ntohs(sa4.sin_port);
conn->tap_port = ref.r.p.tcp.tcp.index;
diff --git a/util.c b/util.c
index 514bd44..257d0b6 100644
--- a/util.c
+++ b/util.c
@@ -482,3 +482,23 @@ int write_file(const char *path, const char *buf)
close(fd);
return len == 0 ? 0 : -1;
}
+
+struct ip4mapped_ip6 {
+ uint8_t zero[10];
+ uint8_t one[2];
+ struct in_addr a4;
+};
+
+/**
+ * encode_ip4mapped_ip6() - Convert an IPv4 address to an IPv4-mapped IPv6 address
+ * @ip6: Buffer to store the IPv4-mapped IPv6 address
+ * @ip4: IPv4 address, network order
+ */
+void encode_ip4mapped_ip6(struct in6_addr *ip6, const void *ip4)
+{
+ struct ip4mapped_ip6 *a = (struct ip4mapped_ip6 *)ip6;
+
+ memset(&a->zero, 0, sizeof(a->zero));
+ memset(&a->one, 0xff, sizeof(a->one));
+ memcpy(&a->a4, ip4, sizeof(a->a4));
+}
diff --git a/util.h b/util.h
index 2d4e1ff..f7d6a6f 100644
--- a/util.h
+++ b/util.h
@@ -209,5 +209,6 @@ void write_pidfile(int fd, pid_t pid);
int __daemon(int pidfile_fd, int devnull_fd);
int fls(unsigned long x);
int write_file(const char *path, const char *buf);
+void encode_ip4mapped_ip6(struct in6_addr *ip6, const void *ip4);
#endif /* UTIL_H */
--
2.38.1