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[Qemu-devel] [PATCH v2 1/4] linux-user: SOCK_PACKET uses network endian
From: |
Laurent Vivier |
Subject: |
[Qemu-devel] [PATCH v2 1/4] linux-user: SOCK_PACKET uses network endian to encode protocol in socket() |
Date: |
Wed, 28 Oct 2015 20:13:00 +0100 |
in PACKET(7) :
packet_socket = socket(AF_PACKET, int socket_type, int protocol);
[...]
protocol is the IEEE 802.3 protocol
number in network order. See the <linux/if_ether.h> include file for a
list of allowed protocols. When protocol is set to htons(ETH_P_ALL)
then all protocols are received. All incoming packets of that protocol
type will be passed to the packet socket before they are passed to the
protocols implemented in the kernel.
[...]
Compatibility
In Linux 2.0, the only way to get a packet socket was by calling
socket(AF_INET, SOCK_PACKET, protocol).
We need to tswap16() the protocol because on big-endian, the ABI is
waiting for, for instance for ETH_P_ALL, 0x0003 (big endian ==
network order), whereas on little-endian it is waiting for 0x0300.
Signed-off-by: Laurent Vivier <address@hidden>
---
linux-user/syscall.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 4b4159d..7c724ab 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -2089,6 +2089,12 @@ static abi_long do_socket(int domain, int type, int
protocol)
if (domain == PF_NETLINK)
return -TARGET_EAFNOSUPPORT;
+
+ if (domain == AF_PACKET ||
+ (domain == AF_INET && type == SOCK_PACKET)) {
+ protocol = tswap16(protocol);
+ }
+
ret = get_errno(socket(domain, type, protocol));
if (ret >= 0) {
ret = sock_flags_fixup(ret, target_type);
--
2.4.3