This is obsolete, but if we want to use dhcp with an old distro (like debian
etch), we need it. Some users (like dhclient) use SOCK_PACKET with AF_PACKET
and the kernel allows that.
packet(7)
In Linux 2.0, the only way to get a packet socket was by calling
socket(AF_INET, SOCK_PACKET, protocol). This is still supported but
strongly deprecated. The main difference between the two methods is
that SOCK_PACKET uses the old struct sockaddr_pkt to specify an inter‐
face, which doesn't provide physical layer independence.
struct sockaddr_pkt {
unsigned short spkt_family;
unsigned char spkt_device[14];
unsigned short spkt_protocol;
};
spkt_family contains the device type, spkt_protocol is the IEEE 802.3
protocol type as defined in <sys/if_ether.h> and spkt_device is the
device name as a null-terminated string, for example, eth0.
Signed-off-by: Laurent Vivier <laur...@vivier.eu>
---
linux-user/syscall.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 31b5c2c..f048437 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -2086,6 +2086,30 @@ static int sock_flags_fixup(int fd, int target_type)
return fd;
}
+static abi_long packet_target_to_host_addr(void *host_addr,
+ abi_ulong target_addr,
+ socklen_t len)
+{
+ struct sockaddr *addr = host_addr;
+ struct target_sockaddr *target_saddr;
+
+ target_saddr = lock_user(VERIFY_READ, target_addr, len, 1);
+ if (!target_saddr) {
+ return -TARGET_EFAULT;
+ }
+
+ memcpy(addr, target_saddr, len);
+ addr->sa_family = tswap16(target_saddr->sa_family);
+ /* spkt_protocol is big-endian */
+
+ unlock_user(target_saddr, target_addr, 0);
+ return 0;
+}
+
+static TargetFdTrans target_packet_trans = {
+ .target_to_host_addr = packet_target_to_host_addr,
+};
+
/* do_socket() Must return target values and target errnos. */
static abi_long do_socket(int domain, int type, int protocol)
{
@@ -2108,6 +2132,12 @@ static abi_long do_socket(int domain, int type, int
protocol)
ret = get_errno(socket(domain, type, protocol));
if (ret >= 0) {
ret = sock_flags_fixup(ret, target_type);
+ if (type == SOCK_PACKET) {
+ /* Manage an obsolete case :
+ * if socket type is SOCK_PACKET, bind by name
+ */
+ fd_trans_register(ret, &target_packet_trans);
+ }
}
return ret;
}
--
2.4.3
