[Qemu-devel] [PATCH 04/12] slirp: add in6_multicast() and use it instead of IN6_IS_ADDR_MULTICAST()

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

Host: Mac OS 10.12.5
Compiler: Apple LLVM version 8.1.0 (clang-802.0.42)

  slirp/ip6_icmp.c:79:32: warning: taking address of packed member 'ip_src' of class or
        structure 'ip6' may result in an unaligned pointer value
        [-Waddress-of-packed-member]
      if (IN6_IS_ADDR_MULTICAST(&ip->ip_src) ||
                                 ^~~~~~~~~~
  /usr/include/netinet6/in6.h:299:36: note: expanded from macro 'IN6_IS_ADDR_MULTICAST'
  #define IN6_IS_ADDR_MULTICAST(a)        ((a)->s6_addr[0] == 0xff)
                                            ^

Reported-by: John Arbuckle <programmingkidx@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 slirp/ip6.h       |  5 +++++
 slirp/ip6_icmp.c  | 10 +++++-----
 slirp/ndp_table.c |  4 ++--
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/slirp/ip6.h b/slirp/ip6.h
index b1bea43b3c..6c5d4eeaa3 100644
--- a/slirp/ip6.h
+++ b/slirp/ip6.h
@@ -93,6 +93,11 @@ static inline bool in6_equal_mach(const struct in6_addr *a,
 #define in6_zero(a)\
     (in6_equal(a, &(struct in6_addr)ZERO_ADDR))
 
+static inline bool in6_multicast(const struct in6_addr *a)
+{
+    return a->s6_addr[0] == 0xff;
+}
+
 /* Compute emulated host MAC address from its ipv6 address */
 static inline void in6_compute_ethaddr(struct in6_addr ip,
                                        uint8_t eth[ETH_ALEN])
diff --git a/slirp/ip6_icmp.c b/slirp/ip6_icmp.c
index ee333d05a2..9796624648 100644
--- a/slirp/ip6_icmp.c
+++ b/slirp/ip6_icmp.c
@@ -76,7 +76,7 @@ void icmp6_send_error(struct mbuf *m, uint8_t type, uint8_t code)
     DEBUG_CALL("icmp6_send_error");
     DEBUG_ARGS((dfd, " type = %d, code = %d\n", type, code));
 
-    if (IN6_IS_ADDR_MULTICAST(&ip->ip_src) ||
+    if (in6_multicast(&ip->ip_src) ||
             in6_zero(&ip->ip_src)) {
         /* TODO icmp error? */
         return;
@@ -291,7 +291,7 @@ static void ndp_send_na(Slirp *slirp, struct ip6 *ip, struct icmp6 *icmp)
 
     /* NDP */
     ricmp->icmp6_nna.R = NDP_IsRouter;
-    ricmp->icmp6_nna.S = !IN6_IS_ADDR_MULTICAST(&rip->ip_dst);
+    ricmp->icmp6_nna.S = !in6_multicast(&rip->ip_dst);
     ricmp->icmp6_nna.O = 1;
     ricmp->icmp6_nna.reserved_hi = 0;
     ricmp->icmp6_nna.reserved_lo = 0;
@@ -348,7 +348,7 @@ static void ndp_input(struct mbuf *m, Slirp *slirp, struct ip6 *ip,
         DEBUG_CALL(" type = Neighbor Solicitation");
         if (ip->ip_hl == 255
                 && icmp->icmp6_code == 0
-                && !IN6_IS_ADDR_MULTICAST(&icmp->icmp6_nns.target)
+                && !in6_multicast(&icmp->icmp6_nns.target)
                 && ntohs(ip->ip_pl) >= ICMP6_NDP_NS_MINLEN
                 && (!in6_zero(&ip->ip_src)
                     || in6_solicitednode_multicast(&ip->ip_dst))) {
@@ -365,8 +365,8 @@ static void ndp_input(struct mbuf *m, Slirp *slirp, struct ip6 *ip,
         if (ip->ip_hl == 255
                 && icmp->icmp6_code == 0
                 && ntohs(ip->ip_pl) >= ICMP6_NDP_NA_MINLEN
-                && !IN6_IS_ADDR_MULTICAST(&icmp->icmp6_nna.target)
-                && (!IN6_IS_ADDR_MULTICAST(&ip->ip_dst)
+                && !in6_multicast(&icmp->icmp6_nna.target)
+                && (!in6_multicast(&ip->ip_dst)
                     || icmp->icmp6_nna.S == 0)) {
             ndp_table_add(slirp, ip->ip_src, eth->h_source);
         }
diff --git a/slirp/ndp_table.c b/slirp/ndp_table.c
index e1676a0a7b..5ff4bf2f3d 100644
--- a/slirp/ndp_table.c
+++ b/slirp/ndp_table.c
@@ -23,7 +23,7 @@ void ndp_table_add(Slirp *slirp, struct in6_addr ip_addr,
                 ethaddr[0], ethaddr[1], ethaddr[2],
                 ethaddr[3], ethaddr[4], ethaddr[5]));
 
-    if (IN6_IS_ADDR_MULTICAST(&ip_addr) || in6_zero(&ip_addr)) {
+    if (in6_multicast(&ip_addr) || in6_zero(&ip_addr)) {
         /* Do not register multicast or unspecified addresses */
         DEBUG_CALL(" abort: do not register multicast or unspecified address");
         return;
@@ -63,7 +63,7 @@ bool ndp_table_search(Slirp *slirp, struct in6_addr ip_addr,
     assert(!in6_zero(&ip_addr));
 
     /* Multicast address: fec0::abcd:efgh/8 -> 33:33:ab:cd:ef:gh */
-    if (IN6_IS_ADDR_MULTICAST(&ip_addr)) {
+    if (in6_multicast(&ip_addr)) {
         out_ethaddr[0] = 0x33; out_ethaddr[1] = 0x33;
         out_ethaddr[2] = ip_addr.s6_addr[12];
         out_ethaddr[3] = ip_addr.s6_addr[13];
-- 
2.15.1