T72: Fix compilations warnings for unaligned variable access

- IPoE/DHCP4: Specify minimal suitable alignment explicitly.
  We need to guarantee 2 byte alignment for the `hdr` pointer in
    `ip_csum(uint16_t *buf)` calculation
- PPPOE: Suppress false-positive warning for `sockaddr_pppox`.
  Similiar issue: https://github.com/kernelslacker/trinity/pull/40
- Introduce tmp variables to avoid alignment issues for SSTP/DHCPv6

For additional details:
https://phabricator.accel-ppp.org/T72

Signed-off-by: Volodymyr Huti <v.huti@vyos.io>

1 files changed, 18 insertions, 13 deletions

diff --git a/accel-pppd/ctrl/sstp/sstp.c b/accel-pppd/ctrl/sstp/sstp.c
index 40c6ad91..a97f4ec5 100644
--- a/accel-pppd/ctrl/sstp/sstp.c
+++ b/accel-pppd/ctrl/sstp/sstp.c
@@ -286,12 +286,15 @@ static int _vstrsep(char *buf, const char *sep, ...)
 
 static in_addr_t sockaddr_ipv4(struct sockaddr_t *addr)
 {
+	struct in6_addr inaddr6;
+
 	switch (addr->u.sa.sa_family) {
 	case AF_INET:
 		return addr->u.sin.sin_addr.s_addr;
 	case AF_INET6:
-		if (IN6_IS_ADDR_V4MAPPED(&addr->u.sin6.sin6_addr))
-			return addr->u.sin6.sin6_addr.s6_addr32[3];
+		inaddr6 = addr->u.sin6.sin6_addr;
+		if (IN6_IS_ADDR_V4MAPPED(&inaddr6))
+			return inaddr6.s6_addr32[3];
 		/* fall through */
 	default:
 		return INADDR_ANY;
@@ -301,22 +304,22 @@ static in_addr_t sockaddr_ipv4(struct sockaddr_t *addr)
 static int sockaddr_ntop(struct sockaddr_t *addr, char *dst, socklen_t size, int flags)
 {
 	char ipv6_buf[INET6_ADDRSTRLEN], *path, sign;
+	struct sockaddr_in6 sin6 = addr->u.sin6;
+	struct in6_addr inaddr6 = sin6.sin6_addr;
 
 	switch (addr->u.sa.sa_family) {
 	case AF_INET:
 		return snprintf(dst, size, (flags & FLAG_NOPORT) ? "%s" : "%s:%d",
 				inet_ntoa(addr->u.sin.sin_addr), ntohs(addr->u.sin.sin_port));
 	case AF_INET6:
-		if (IN6_IS_ADDR_V4MAPPED(&addr->u.sin6.sin6_addr)) {
-			inet_ntop(AF_INET, &addr->u.sin6.sin6_addr.s6_addr32[3],
-					ipv6_buf, sizeof(ipv6_buf));
+		if (IN6_IS_ADDR_V4MAPPED(&inaddr6)) {
+			inet_ntop(AF_INET, &inaddr6.s6_addr32[3], ipv6_buf, sizeof(ipv6_buf));
 			return snprintf(dst, size, (flags & FLAG_NOPORT) ? "%s" : "%s:%d",
-					ipv6_buf, ntohs(addr->u.sin6.sin6_port));
+					ipv6_buf, ntohs(sin6.sin6_port));
 		} else {
-			inet_ntop(AF_INET6, &addr->u.sin6.sin6_addr,
-					ipv6_buf, sizeof(ipv6_buf));
+			inet_ntop(AF_INET6, &inaddr6, ipv6_buf, sizeof(ipv6_buf));
 			return snprintf(dst, size, (flags & FLAG_NOPORT) ? "%s" : "[%s]:%d",
-					ipv6_buf, ntohs(addr->u.sin6.sin6_port));
+					ipv6_buf, ntohs(sin6.sin6_port));
 		}
 	case AF_UNIX:
 		if (addr->len <= offsetof(typeof(addr->u.sun), sun_path)) {
@@ -2276,12 +2279,14 @@ static int sstp_connect(struct triton_md_handler_t *h)
 	struct sstp_conn_t *conn;
 	struct sockaddr_t addr;
 	char addr_buf[ADDRSTR_MAXLEN];
+	socklen_t addrlen;
 	in_addr_t ip;
 	int sock, value;
 
 	while (1) {
-		addr.len = sizeof(addr.u);
-		sock = accept(h->fd, &addr.u.sa, &addr.len);
+		addrlen = sizeof(addr.u);
+		sock = accept(h->fd, &addr.u.sa, &addrlen);
+		addr.len = addrlen;
 		if (sock < 0) {
 			if (errno == EAGAIN)
 				return 0;
@@ -2408,8 +2413,8 @@ static int sstp_connect(struct triton_md_handler_t *h)
 		sockaddr_ntop(&addr, addr_buf, sizeof(addr_buf), FLAG_NOPORT);
 		conn->ctrl.calling_station_id = _strdup(addr_buf);
 
-		addr.len = sizeof(addr.u);
-		getsockname(sock, &addr.u.sa, &addr.len);
+		addrlen = sizeof(addr.u);
+		getsockname(sock, &addr.u.sa, &addrlen);
 		sockaddr_ntop(&addr, addr_buf, sizeof(addr_buf), FLAG_NOPORT);
 		conn->ctrl.called_station_id = _strdup(addr_buf);