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>

5 files changed, 35 insertions, 22 deletions

diff --git a/accel-pppd/ctrl/ipoe/dhcpv4.c b/accel-pppd/ctrl/ipoe/dhcpv4.c
index f1d9c46..41cbe50 100644
--- a/accel-pppd/ctrl/ipoe/dhcpv4.c
+++ b/accel-pppd/ctrl/ipoe/dhcpv4.c
@@ -625,7 +625,7 @@ static int dhcpv4_send_raw(struct dhcpv4_serv *serv, struct dhcpv4_packet *pack,
 		struct iphdr ip;
 		struct udphdr udp;
 		uint8_t data[0];
-	} __packed *hdr;
+	} __packed __aligned(2) *hdr;
 	struct sockaddr_ll ll_addr;
 	int n, len = pack->ptr - pack->data;
 
diff --git a/accel-pppd/ctrl/ipoe/dhcpv4.h b/accel-pppd/ctrl/ipoe/dhcpv4.h
index 8598b61..796b858 100644
--- a/accel-pppd/ctrl/ipoe/dhcpv4.h
+++ b/accel-pppd/ctrl/ipoe/dhcpv4.h
@@ -8,6 +8,7 @@
 
 #include "triton.h"
 
+#define __aligned(n) __attribute__((aligned (n)))
 #define __packed __attribute__((packed))
 
 #define DHCP_SERV_PORT 67
diff --git a/accel-pppd/ctrl/pppoe/pppoe.c b/accel-pppd/ctrl/pppoe/pppoe.c
index 43163f1..44b094b 100644
--- a/accel-pppd/ctrl/pppoe/pppoe.c
+++ b/accel-pppd/ctrl/pppoe/pppoe.c
@@ -433,6 +433,8 @@ static struct pppoe_conn_t *allocate_channel(struct pppoe_serv_t *serv, const ui
 	return conn;
 }
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Waddress-of-packed-member"
 static void connect_channel(struct pppoe_conn_t *conn)
 {
 	int sock;
@@ -486,6 +488,7 @@ out_err_close:
 out_err:
 	disconnect(conn);
 }
+#pragma GCC diagnostic pop
 
 static struct pppoe_conn_t *find_channel(struct pppoe_serv_t *serv, const uint8_t *cookie)
 {
diff --git a/accel-pppd/ctrl/sstp/sstp.c b/accel-pppd/ctrl/sstp/sstp.c
index 40c6ad9..a97f4ec 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);
 
diff --git a/accel-pppd/ipv6/dhcpv6.c b/accel-pppd/ipv6/dhcpv6.c
index cefbcfd..158771b 100644
--- a/accel-pppd/ipv6/dhcpv6.c
+++ b/accel-pppd/ipv6/dhcpv6.c
@@ -244,8 +244,8 @@ static void dhcpv6_send_reply(struct dhcpv6_packet *req, struct dhcpv6_pd *pd, i
 	struct dhcpv6_opt_ia_na *ia_na;
 	struct dhcpv6_opt_ia_addr *ia_addr;
 	struct dhcpv6_opt_ia_prefix *ia_prefix;
+	struct in6_addr addr, prefix;
 	struct ipv6db_addr_t *a;
-	struct in6_addr addr;
 	struct ap_session *ses = req->ses;
 	int f = 0, f1, f2 = 0;
 
@@ -282,7 +282,8 @@ static void dhcpv6_send_reply(struct dhcpv6_packet *req, struct dhcpv6_pd *pd, i
 					opt2 = dhcpv6_nested_option_alloc(reply, opt1, D6_OPTION_IAADDR, sizeof(*ia_addr) - sizeof(struct dhcpv6_opt_hdr));
 					ia_addr = (struct dhcpv6_opt_ia_addr *)opt2->hdr;
 
-					build_ip6_addr(a, ses->ipv6->peer_intf_id, &ia_addr->addr);
+					build_ip6_addr(a, ses->ipv6->peer_intf_id, &addr);
+					memcpy(&ia_addr->addr, &addr, sizeof(addr));
 
 					ia_addr->pref_lifetime = htonl(conf_pref_lifetime);
 					ia_addr->valid_lifetime = htonl(conf_valid_lifetime);
@@ -309,8 +310,9 @@ static void dhcpv6_send_reply(struct dhcpv6_packet *req, struct dhcpv6_pd *pd, i
 					list_for_each_entry(opt2, &opt->opt_list, entry) {
 						if (ntohs(opt2->hdr->code) == D6_OPTION_IAADDR) {
 							ia_addr = (struct dhcpv6_opt_ia_addr *)opt2->hdr;
+							addr = ia_addr->addr;
 
-							if (IN6_IS_ADDR_UNSPECIFIED(&ia_addr->addr))
+							if (IN6_IS_ADDR_UNSPECIFIED(&addr))
 								continue;
 
 							f1 = 0;
@@ -389,8 +391,9 @@ static void dhcpv6_send_reply(struct dhcpv6_packet *req, struct dhcpv6_pd *pd, i
 					list_for_each_entry(opt2, &opt->opt_list, entry) {
 						if (ntohs(opt2->hdr->code) == D6_OPTION_IAPREFIX) {
 							ia_prefix = (struct dhcpv6_opt_ia_prefix *)opt2->hdr;
+							prefix = ia_prefix->prefix;
 
-							if (ia_prefix->prefix_len == 0 || IN6_IS_ADDR_UNSPECIFIED(&ia_prefix->prefix))
+							if (ia_prefix->prefix_len == 0 || IN6_IS_ADDR_UNSPECIFIED(&prefix))
 								continue;
 
 							f1 = 0;
@@ -464,7 +467,7 @@ static void dhcpv6_send_reply2(struct dhcpv6_packet *req, struct dhcpv6_pd *pd,
 	struct dhcpv6_opt_ia_addr *ia_addr;
 	struct dhcpv6_opt_ia_prefix *ia_prefix;
 	struct ipv6db_addr_t *a;
-	struct in6_addr addr;
+	struct in6_addr addr, prefix;
 	struct ap_session *ses = req->ses;
 	int f = 0, f1, f2 = 0, f3;
 
@@ -488,8 +491,8 @@ static void dhcpv6_send_reply2(struct dhcpv6_packet *req, struct dhcpv6_pd *pd,
 			list_for_each_entry(opt2, &opt->opt_list, entry) {
 				if (ntohs(opt2->hdr->code) == D6_OPTION_IAADDR) {
 					ia_addr = (struct dhcpv6_opt_ia_addr *)opt2->hdr;
-
-					if (IN6_IS_ADDR_UNSPECIFIED(&ia_addr->addr))
+					addr = ia_addr->addr;
+					if (IN6_IS_ADDR_UNSPECIFIED(&addr))
 						continue;
 
 					f1 = 0;
@@ -550,8 +553,9 @@ static void dhcpv6_send_reply2(struct dhcpv6_packet *req, struct dhcpv6_pd *pd,
 			list_for_each_entry(opt2, &opt->opt_list, entry) {
 				if (ntohs(opt2->hdr->code) == D6_OPTION_IAPREFIX) {
 					ia_prefix = (struct dhcpv6_opt_ia_prefix *)opt2->hdr;
+					prefix = ia_prefix->prefix;
 
-					if (ia_prefix->prefix_len == 0 || IN6_IS_ADDR_UNSPECIFIED(&ia_prefix->prefix))
+					if (ia_prefix->prefix_len == 0 || IN6_IS_ADDR_UNSPECIFIED(&prefix))
 						continue;
 
 					f1 = 0;