Pack IP structures directly used for access packet data.

All structures used to access data in byte buffers shall be marked
as packed. Otherwise, this is undefined behavior - formally on
every platform.

sys/netinet/dccp.h

@@ -66,7 +66,7 @@ struct dccphdr {
                        uint8_t seq[6];
                } longseq;
        } d_seqno;
-};
+}  __packed;
 
 #define d_seqno_short d_seqno.shortseq;
 #define d_seqno_long d_seqno.longseq.seq;

sys/netinet/ip.h

@@ -69,7 +69,7 @@ struct ip {
 	u_char	ip_p;			/* protocol */
 	u_short	ip_sum;			/* checksum */
 	struct	in_addr ip_src,ip_dst;	/* source and dest address */
-} __packed __aligned(2);
+} __packed;
 
 #define	IP_MAXPACKET	65535		/* maximum packet size */
 
@@ -189,7 +189,7 @@ struct	ip_timestamp {
 			uint32_t ipt_time;	/* network format */
 		} ipt_ta[1];
 	} ipt_timestamp;
-};
+} __packed;
 
 /* Flag bits for ipt_flg. */
 #define	IPOPT_TS_TSONLY		0		/* timestamps only */

sys/netinet/ip_var.h

@@ -50,7 +50,7 @@ struct ipovly {
 	u_short	ih_len;			/* protocol length */
 	struct	in_addr ih_src;		/* source internet address */
 	struct	in_addr ih_dst;		/* destination internet address */
-};
+} __packed;
 
 #ifdef _KERNEL
 /*

sys/netinet/pim.h

@@ -73,7 +73,7 @@ struct pim {
 #endif /* ! _PIM_VT  */
 	uint8_t		pim_reserved;	/* Reserved			*/
 	uint16_t	pim_cksum;	/* IP-style checksum		*/
-};
+} __packed;
 /* KAME-related name backward compatibility */
 #define pim_ver pim_vers
 #define pim_rsv pim_reserved

sys/netinet/tcp.h

@@ -81,7 +81,7 @@ struct tcphdr {
 	u_short	th_win;			/* window */
 	u_short	th_sum;			/* checksum */
 	u_short	th_urp;			/* urgent pointer */
-};
+} __packed;
 
 #define	PADTCPOLEN(len)		((((len) / 4) + !!((len) % 4)) * 4)
 

sys/netinet/udp.h

@@ -47,7 +47,7 @@ struct udphdr {
 	u_short	uh_dport;		/* destination port */
 	u_short	uh_ulen;		/* udp length */
 	u_short	uh_sum;			/* udp checksum */
-};
+} __packed;
 
 /*
  * User-settable options (used with setsockopt).