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[Qemu-devel] [PATCH v3 4/5] linux-user: manage bind with a socket of SOC
From: |
Laurent Vivier |
Subject: |
[Qemu-devel] [PATCH v3 4/5] linux-user: manage bind with a socket of SOCK_PACKET type. |
Date: |
Wed, 28 Oct 2015 21:40:45 +0100 |
This is obsolete, but if we want to use dhcp with an old distro (like debian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 <address@hidden>
---
v3: rename packet_target_to_host_addr to packet_target_to_host_sockaddr
linux-user/syscall.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index a313846..22b28a4 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -2090,6 +2090,30 @@ static int sock_flags_fixup(int fd, int target_type)
return fd;
}
+static abi_long packet_target_to_host_sockaddr(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_sockaddr,
+};
+
/* do_socket() Must return target values and target errnos. */
static abi_long do_socket(int domain, int type, int protocol)
{
@@ -2112,6 +2136,12 @@ 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
- [Qemu-devel] [PATCH v3 0/5] linux-user: manage SOCK_PACKET socket type, Laurent Vivier, 2015/10/28
- [Qemu-devel] [PATCH v3 4/5] linux-user: manage bind with a socket of SOCK_PACKET type.,
Laurent Vivier <=
- [Qemu-devel] [PATCH v3 5/5] linux-user: check fd is >= 0 in fd_trans_host_to_target_data/fd_trans_host_to_target_addr, Laurent Vivier, 2015/10/28
- [Qemu-devel] [PATCH v3 1/5] linux-user: SOCK_PACKET uses network endian to encode protocol in socket(), Laurent Vivier, 2015/10/28
- [Qemu-devel] [PATCH v3 2/5] linux-user: rename TargetFdFunc to TargetFdDataFunc, and structure fields accordingly, Laurent Vivier, 2015/10/28
- [Qemu-devel] [PATCH v3 3/5] linux-user: add a function hook to translate sockaddr, Laurent Vivier, 2015/10/28
- Re: [Qemu-devel] [PATCH v3 0/5] linux-user: manage SOCK_PACKET socket type, Peter Maydell, 2015/10/28