[tcpip] Allow binding to unspecified privileged ports (below 1024)

Originally-implemented-by: Marin Hannache <git@mareo.fr>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/in.h

@@ -59,19 +59,22 @@ struct sockaddr_in {
 	 * Always set to @c AF_INET for IPv4 addresses
 	 */
 	sa_family_t sin_family;
+	/** Flags (part of struct @c sockaddr_tcpip) */
+	uint16_t sin_flags;
 	/** TCP/IP port (part of struct @c sockaddr_tcpip) */
 	uint16_t sin_port;
 	/** IPv4 address */
 	struct in_addr sin_addr;
 	/** Padding
 	 *
-	 * This ensures that a struct @c sockaddr_tcpip is large
-	 * enough to hold a socket address for any TCP/IP address
-	 * family.
+	 * This ensures that a struct @c sockaddr_in is large enough
+	 * to hold a socket address for any TCP/IP address family.
 	 */
-	char pad[ sizeof ( struct sockaddr ) - sizeof ( sa_family_t )
-					     - sizeof ( uint16_t )
-					     - sizeof ( struct in_addr ) ];
+	char pad[ sizeof ( struct sockaddr ) -
+		  ( sizeof ( sa_family_t ) /* sin_family */ +
+		    sizeof ( uint16_t ) /* sin_flags */ +
+		    sizeof ( uint16_t ) /* sin_port */ +
+		    sizeof ( struct in_addr ) /* sin_addr */ ) ];
 } __attribute__ (( may_alias ));
 
 /**
@@ -83,11 +86,26 @@ struct sockaddr_in6 {
 	 * Always set to @c AF_INET6 for IPv6 addresses
 	 */
 	sa_family_t sin6_family;
+	/** Flags (part of struct @c sockaddr_tcpip) */
+	uint16_t sin6_flags;
 	/** TCP/IP port (part of struct @c sockaddr_tcpip) */
 	uint16_t sin6_port;
         uint32_t        sin6_flowinfo;  /* Flow number */
         struct in6_addr sin6_addr;      /* 128-bit destination address */
         uint32_t        sin6_scope_id;  /* Scope ID */
+	/** Padding
+	 *
+	 * This ensures that a struct @c sockaddr_in6 is large
+	 * enough to hold a socket address for any TCP/IP address
+	 * family.
+	 */
+	char pad[ sizeof ( struct sockaddr ) -
+		  ( sizeof ( sa_family_t ) /* sin6_family */ +
+		    sizeof ( uint16_t ) /* sin6_flags */ +
+		    sizeof ( uint16_t ) /* sin6_port */ +
+		    sizeof ( uint32_t ) /* sin6_flowinfo */ +
+		    sizeof ( struct in6_addr ) /* sin6_addr */ +
+		    sizeof ( uint32_t ) /* sin6_scope_id */ ) ];
 } __attribute__ (( may_alias ));
 
 extern int inet_aton ( const char *cp, struct in_addr *inp );

src/include/ipxe/tcpip.h

@@ -24,6 +24,16 @@ struct net_device;
  */
 #define TCPIP_EMPTY_CSUM 0xffff
 
+/** TCP/IP address flags */
+enum tcpip_st_flags {
+	/** Bind to a privileged port (less than 1024)
+	 *
+	 * This value is chosen as 1024 to optimise the calculations
+	 * in tcpip_bind().
+	 */
+	TCPIP_BIND_PRIVILEGED = 0x0400,
+};
+
 /**
  * TCP/IP socket address
  *
@@ -33,6 +43,8 @@ struct net_device;
 struct sockaddr_tcpip {
 	/** Socket address family (part of struct @c sockaddr) */
 	sa_family_t st_family;
+	/** Flags */
+	uint16_t st_flags;
 	/** TCP/IP port */
 	uint16_t st_port;
 	/** Padding
@@ -42,7 +54,9 @@ struct sockaddr_tcpip {
 	 * family.
 	 */
 	char pad[ sizeof ( struct sockaddr ) -
-		  ( sizeof ( sa_family_t ) + sizeof ( uint16_t ) ) ];
+		  ( sizeof ( sa_family_t ) /* st_family */ +
+		    sizeof ( uint16_t ) /* st_flags */ +
+		    sizeof ( uint16_t ) /* st_port */ ) ];
 } __attribute__ (( may_alias ));
 
 /** 
@@ -125,6 +139,8 @@ extern int tcpip_tx ( struct io_buffer *iobuf, struct tcpip_protocol *tcpip,
 extern uint16_t generic_tcpip_continue_chksum ( uint16_t partial,
 						const void *data, size_t len );
 extern uint16_t tcpip_chksum ( const void *data, size_t len );
+extern int tcpip_bind ( struct sockaddr_tcpip *st_local,
+			int ( * available ) ( int port ) );
 
 /* Use generic_tcpip_continue_chksum() if no architecture-specific
  * version is available