[Qemu-devel] [PATCH v2 4/5] linux-user: setsockopt(): Add support for the option IPV6_ADD_MEMBERSHIP

[Aleksandar Markovic]

From: Neng Chen <address@hidden>

Add support for the option IPV6_ADD_MEMBERSHIP of the syscall
setsockopt(). This option controls membership in multicast groups.
Argument is a pointer to a struct ipv6_mreq, which is in turn defined
in a platform-inedependant manner in the Linux kernel file
include/uapi/linux/in6.h as:

The <netinet/in.h> header defines the ipv6_mreq structure, which
includes the following members:

struct in6_addr ipv6mr_multiaddr  /* IPv6 multicast address   */
unsigned int    ipv6mr_interface  /* local interface index    */

struct ipv6_mreq {
    /* IPv6 multicast address of group */
    struct in6_addr  ipv6mr_multiaddr;

    /* local IPv6 address of interface */
    int              ipv6mr_ifindex;
};

The <netinet/in.h> header also defines the in6_addr structure,
which a union of the following structure:

struct in6_addr {
    union {
        __u8    u6_addr8[16];
        __be16  u6_addr16[8];
        __be32  u6_addr32[4];
    } in6_u;

The emulation behavior of IPV6_ADD_MEMBERSHIP is devised based on
the definitions above.

Signed-off-by: Neng Chen <address@hidden>
Signed-off-by: Aleksandar Markovic <address@hidden>
---
 linux-user/syscall.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 96cd4bf..b47a45d 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -1892,6 +1892,24 @@ static abi_long do_setsockopt(int sockfd, int level, int 
optname,
                                        &pki, sizeof(pki)));
             break;
         }
+        case IPV6_ADD_MEMBERSHIP:
+        {
+            struct ipv6_mreq ipv6mreq;
+
+            if (optlen < sizeof(ipv6mreq)) {
+                return -TARGET_EINVAL;
+            }
+
+            if (copy_from_user(&ipv6mreq, optval_addr, sizeof(ipv6mreq))) {
+                return -TARGET_EFAULT;
+            }
+
+            ipv6mreq.ipv6mr_interface = tswap32(ipv6mreq.ipv6mr_interface);
+
+            ret = get_errno(setsockopt(sockfd, level, optname,
+                                       &ipv6mreq, sizeof(ipv6mreq)));
+            break;
+        }
         default:
             goto unimplemented;
         }
-- 
2.7.4