Fix `ipfw fwd tablearg'. Use dedicated field nh4 in struct table_value

to obtain IPv4 next hop address in tablearg case.

Add `fwd tablearg' support for IPv6. ipfw(8) uses INADDR_ANY as next hop
address in O_FORWARD_IP opcode for specifying tablearg case. For IPv6 we
still use this opcode, but when packet identified as IPv6 packet, we
obtain next hop address from dedicated field nh6 in struct table_value.

Replace hopstore field in struct ip_fw_args with anonymous union and add
hopstore6 field. Use this field to copy tablearg value for IPv6.

Replace spare1 field in struct table_value with zoneid. Use it to keep
scope zone id for link-local IPv6 addresses. Since spare1 was used
internally, replace spare0 array with two variables spare0 and spare1.

Use getaddrinfo(3)/getnameinfo(3) functions for parsing and formatting
IPv6 addresses in table_value. Use zoneid field in struct table_value
to store sin6_scope_id value.

Since the kernel still uses embedded scope zone id to represent
link-local addresses, convert next_hop6 address into this form before
return from pfil processing. This also fixes in6_localip() check
for link-local addresses.

Differential Revision:	https://reviews.freebsd.org/D2015
Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC

1 files changed, 15 insertions, 2 deletions

diff --git a/sys/netpfil/ipfw/ip_fw_pfil.c b/sys/netpfil/ipfw/ip_fw_pfil.c
index b53a8ce..61f182d 100644
--- a/sys/netpfil/ipfw/ip_fw_pfil.c
+++ b/sys/netpfil/ipfw/ip_fw_pfil.c
@@ -59,6 +59,7 @@ __FBSDID("$FreeBSD$");
 #ifdef INET6
 #include <netinet/ip6.h>
 #include <netinet6/ip6_var.h>
+#include <netinet6/scope6_var.h>
 #endif
 
 #include <netgraph/ng_ipfw.h>
@@ -197,8 +198,20 @@ again:
 		}
 #ifdef INET6
 		if (args.next_hop6 != NULL) {
-			bcopy(args.next_hop6, (fwd_tag+1), len);
-			if (in6_localip(&args.next_hop6->sin6_addr))
+			struct sockaddr_in6 *sa6;
+
+			sa6 = (struct sockaddr_in6 *)(fwd_tag + 1);
+			bcopy(args.next_hop6, sa6, len);
+			/*
+			 * If nh6 address is link-local we should convert
+			 * it to kernel internal form before doing any
+			 * comparisons.
+			 */
+			if (sa6_embedscope(sa6, V_ip6_use_defzone) != 0) {
+				ret = EACCES;
+				break;
+			}
+			if (in6_localip(&sa6->sin6_addr))
 				(*m0)->m_flags |= M_FASTFWD_OURS;
 			(*m0)->m_flags |= M_IP6_NEXTHOP;
 		}