We now only extract the v4 part of the tcp_conn::a union in one place.
Make this neater by using a helper to extract the IPv4 address from the
mapped address in that place.
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
tcp.c | 40 +++++++++++++++-------------------------
util.c | 13 +++++++++++++
util.h | 1 +
3 files changed, 29 insertions(+), 25 deletions(-)
diff --git a/tcp.c b/tcp.c
index 3816a1c..6634abb 100644
--- a/tcp.c
+++ b/tcp.c
@@ -416,10 +416,7 @@ struct tcp6_l2_head { /* For MSS6 macro: keep in sync with
tcp6_l2_buf_t */
* @ws_to_tap: Window scaling factor advertised to tap/guest
* @sndbuf: Sending buffer in kernel, rounded to 2 ^ SNDBUF_BITS
* @seq_dup_ack_approx: Last duplicate ACK number sent to tap
- * @a.a6: IPv6 remote address, can be IPv4-mapped
- * @a.a4.zero: Zero prefix for IPv4-mapped, see RFC 6890, Table 20
- * @a.a4.one: Ones prefix for IPv4-mapped
- * @a.a4.a: IPv4 address
+ * @addr: IPv6 remote address, can be IPv4-mapped
* @tap_port: Guest-facing tap port
* @sock_port: Remote, socket-facing port
* @wnd_from_tap: Last window size from tap, unscaled (as received)
@@ -489,15 +486,8 @@ struct tcp_conn {
uint8_t seq_dup_ack_approx;
- union {
- struct in6_addr a6;
- struct {
- uint8_t zero[10];
- uint8_t one[2];
- struct in_addr a;
- } a4;
- } a;
-#define CONN_V4(conn) IN6_IS_ADDR_V4MAPPED(&conn->a.a6)
+ struct in6_addr addr;
+#define CONN_V4(conn) IN6_IS_ADDR_V4MAPPED(&conn->addr)
#define CONN_V6(conn) (!CONN_V4(conn))
in_port_t tap_port;
@@ -960,7 +950,7 @@ static int tcp_rtt_dst_low(const struct tcp_conn *conn)
int i;
for (i = 0; i < LOW_RTT_TABLE_SIZE; i++)
- if (IN6_ARE_ADDR_EQUAL(&conn->a.a6, low_rtt_dst + i))
+ if (IN6_ARE_ADDR_EQUAL(&conn->addr, low_rtt_dst + i))
return 1;
return 0;
@@ -982,7 +972,7 @@ static void tcp_rtt_dst_check(const struct tcp_conn *conn,
return;
for (i = 0; i < LOW_RTT_TABLE_SIZE; i++) {
- if (IN6_ARE_ADDR_EQUAL(&conn->a.a6, low_rtt_dst + i))
+ if (IN6_ARE_ADDR_EQUAL(&conn->addr, low_rtt_dst + i))
return;
if (hole == -1 && IN6_IS_ADDR_UNSPECIFIED(low_rtt_dst + i))
hole = i;
@@ -994,10 +984,10 @@ static void tcp_rtt_dst_check(const struct tcp_conn *conn,
if (hole == -1)
return;
- memcpy(low_rtt_dst + hole++, &conn->a.a6, sizeof(conn->a.a6));
+ memcpy(low_rtt_dst + hole++, &conn->addr, sizeof(conn->addr));
if (hole == LOW_RTT_TABLE_SIZE)
hole = 0;
- memcpy(low_rtt_dst + hole, &in6addr_any, sizeof(conn->a.a6));
+ memcpy(low_rtt_dst + hole, &in6addr_any, sizeof(conn->addr));
#else
(void)conn;
(void)tinfo;
@@ -1285,7 +1275,7 @@ static int tcp_hash_match(const struct tcp_conn *conn,
const struct in6_addr *addr,
in_port_t tap_port, in_port_t sock_port)
{
- if (IN6_ARE_ADDR_EQUAL(&conn->a.a6, addr) &&
+ if (IN6_ARE_ADDR_EQUAL(&conn->addr, addr) &&
conn->tap_port == tap_port && conn->sock_port == sock_port)
return 1;
@@ -1330,7 +1320,7 @@ static void tcp_hash_insert(const struct ctx *c, struct tcp_conn
*conn)
{
int b;
- b = tcp_hash(c, &conn->a.a6, conn->tap_port, conn->sock_port);
+ b = tcp_hash(c, &conn->addr, conn->tap_port, conn->sock_port);
conn->next_index = tc_hash[b] ? tc_hash[b] - tc : -1;
tc_hash[b] = conn;
conn->hash_bucket = b;
@@ -1660,7 +1650,7 @@ do { \
ip_len = plen + sizeof(struct ipv6hdr) + sizeof(struct tcphdr);
b->ip6h.payload_len = htons(plen + sizeof(struct tcphdr));
- b->ip6h.saddr = conn->a.a6;
+ b->ip6h.saddr = conn->addr;
if (IN6_IS_ADDR_LINKLOCAL(&b->ip6h.saddr))
b->ip6h.daddr = c->ip6.addr_ll_seen;
else
@@ -1684,7 +1674,7 @@ do { \
ip_len = plen + sizeof(struct iphdr) + sizeof(struct tcphdr);
b->iph.tot_len = htons(ip_len);
- b->iph.saddr = conn->a.a4.a.s_addr;
+ b->iph.saddr = decode_ip4mapped_ip6(&conn->addr).s_addr;
b->iph.daddr = c->ip4.addr_seen.s_addr;
if (check)
@@ -2202,12 +2192,12 @@ static void tcp_conn_from_tap(struct ctx *c, int af, const void
*addr,
sa = (struct sockaddr *)&addr4;
sl = sizeof(addr4);
- encode_ip4mapped_ip6(&conn->a.a6, addr);
+ encode_ip4mapped_ip6(&conn->addr, addr);
} else {
sa = (struct sockaddr *)&addr6;
sl = sizeof(addr6);
- memcpy(&conn->a.a6, addr, sizeof(conn->a.a6));
+ memcpy(&conn->addr, addr, sizeof(conn->addr));
}
conn->sock_port = ntohs(th->dest);
@@ -2869,7 +2859,7 @@ static void tcp_conn_from_sock(struct ctx *c, union epoll_ref ref,
memcpy(&sa6.sin6_addr, src, sizeof(*src));
}
- memcpy(&conn->a.a6, &sa6.sin6_addr, sizeof(conn->a.a6));
+ memcpy(&conn->addr, &sa6.sin6_addr, sizeof(conn->addr));
conn->sock_port = ntohs(sa6.sin6_port);
conn->tap_port = ref.r.p.tcp.tcp.index;
@@ -2888,7 +2878,7 @@ static void tcp_conn_from_sock(struct ctx *c, union epoll_ref ref,
IN4_ARE_ADDR_EQUAL(&sa4.sin_addr, &c->ip4.addr_seen))
sa4.sin_addr = c->ip4.gw;
- encode_ip4mapped_ip6(&conn->a.a6, &sa4.sin_addr);
+ encode_ip4mapped_ip6(&conn->addr, &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 257d0b6..ec7f57f 100644
--- a/util.c
+++ b/util.c
@@ -502,3 +502,16 @@ void encode_ip4mapped_ip6(struct in6_addr *ip6, const void *ip4)
memset(&a->one, 0xff, sizeof(a->one));
memcpy(&a->a4, ip4, sizeof(a->a4));
}
+
+/**
+ * decode_ip4mapped_ip6() - Decode an IPv4-mapped IPv6 address
+ * @ip6: IPv6 address
+ *
+ * Returns: IPv4 address
+ */
+struct in_addr decode_ip4mapped_ip6(const struct in6_addr *ip6)
+{
+ const struct ip4mapped_ip6 *a = (const struct ip4mapped_ip6 *)ip6;
+
+ return a->a4;
+}
diff --git a/util.h b/util.h
index f7d6a6f..103211d 100644
--- a/util.h
+++ b/util.h
@@ -210,5 +210,6 @@ 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);
+struct in_addr decode_ip4mapped_ip6(const struct in6_addr *ip6);
#endif /* UTIL_H */
--
2.38.1