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l2_packet: Add build option to disable Linux packet socket workaround 

Linux packet socket workaround(*) has an impact in performance when the
workaround socket needs to be kept open to receive EAPOL frames. While
this is normally avoided with a kernel that has the issue addressed by
closing the workaround packet socket when detecting a frame through the
main socket, it is possible for that mechanism to not be sufficient,
e.g., when an open network connection (no EAPOL frames) is used.

Add a build option (CONFIG_NO_LINUX_PACKET_SOCKET_WAR=y) to disable the
workaround. This build option is disabled by default and can be enabled
explicitly on distributions which have an older kernel or a fix for the
kernel regression.

Also remove the unused variable num_rx.

(*) Linux kernel commit 576eb62598f10c8c7fd75703fe89010cdcfff596
('bridge: respect RFC2863 operational state') from 2012 introduced a
regression for using wpa_supplicant with EAPOL frames and a station
interface in a bridge.

Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com>
This commit is contained in:
Mohammed Shafi Shajakhan 2015-10-19 12:40:42 +05:30 committed by Jouni Malinen
parent fde35be9b1
commit 67deaa582d
3 changed files with 25 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
src/l2_packet/l2_packet_linux.c
View File

@ -30,11 +30,13 @@ struct l2_packet_data {
int l2_hdr; /* whether to include layer 2 (Ethernet) header data
* buffers */
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
/* For working around Linux packet socket behavior and regression. */
int fd_br_rx;
int last_from_br;
u8 last_hash[SHA1_MAC_LEN];
unsigned int num_rx, num_rx_br;
unsigned int num_rx_br;
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
};
/* Generated by 'sudo tcpdump -s 3000 -dd greater 278 and ip and udp and
@ -127,7 +129,6 @@ static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
struct sockaddr_ll ll;
socklen_t fromlen;
l2->num_rx++;
os_memset(&ll, 0, sizeof(ll));
fromlen = sizeof(ll);
res = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *) &ll,
@ -141,6 +142,7 @@ static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
wpa_printf(MSG_DEBUG, "%s: src=" MACSTR " len=%d",
__func__, MAC2STR(ll.sll_addr), (int) res);
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
if (l2->fd_br_rx >= 0) {
u8 hash[SHA1_MAC_LEN];
const u8 *addr[1];
@ -173,10 +175,12 @@ static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
}
l2->last_from_br = 0;
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
l2->rx_callback(l2->rx_callback_ctx, ll.sll_addr, buf, res);
}
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
static void l2_packet_receive_br(int sock, void *eloop_ctx, void *sock_ctx)
{
struct l2_packet_data *l2 = eloop_ctx;
@ -214,6 +218,7 @@ static void l2_packet_receive_br(int sock, void *eloop_ctx, void *sock_ctx)
os_memcpy(l2->last_hash, hash, SHA1_MAC_LEN);
l2->rx_callback(l2->rx_callback_ctx, ll.sll_addr, buf, res);
}
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
struct l2_packet_data * l2_packet_init(
@ -233,7 +238,9 @@ struct l2_packet_data * l2_packet_init(
l2->rx_callback = rx_callback;
l2->rx_callback_ctx = rx_callback_ctx;
l2->l2_hdr = l2_hdr;
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
l2->fd_br_rx = -1;
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
l2->fd = socket(PF_PACKET, l2_hdr ? SOCK_RAW : SOCK_DGRAM,
htons(protocol));
@ -289,6 +296,7 @@ struct l2_packet_data * l2_packet_init_bridge(
void *rx_callback_ctx, int l2_hdr)
{
struct l2_packet_data *l2;
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
struct sock_filter ethertype_sock_filter_insns[] = {
/* Load ethertype */
BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 2 * ETH_ALEN),
@ -304,12 +312,14 @@ struct l2_packet_data * l2_packet_init_bridge(
.filter = ethertype_sock_filter_insns,
};
struct sockaddr_ll ll;
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
l2 = l2_packet_init(br_ifname, own_addr, protocol, rx_callback,
rx_callback_ctx, l2_hdr);
if (!l2)
return NULL;
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
/*
* The Linux packet socket behavior has changed over the years and there
* is an inconvenient regression in it that breaks RX for a specific
@ -357,6 +367,7 @@ struct l2_packet_data * l2_packet_init_bridge(
}
eloop_register_read_sock(l2->fd_br_rx, l2_packet_receive_br, l2, NULL);
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
return l2;
}
@ -372,10 +383,12 @@ void l2_packet_deinit(struct l2_packet_data *l2)
close(l2->fd);
}
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
if (l2->fd_br_rx >= 0) {
eloop_unregister_read_sock(l2->fd_br_rx);
close(l2->fd_br_rx);
}
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
os_free(l2);
}

4
wpa_supplicant/Makefile
View File

@ -1453,6 +1453,10 @@ ifdef CONFIG_IPV6
CFLAGS += -DCONFIG_IPV6
endif
ifdef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
CFLAGS += -DCONFIG_NO_LINUX_PACKET_SOCKET_WAR
endif
ifdef NEED_BASE64
OBJS += ../src/utils/base64.o
endif

6
wpa_supplicant/defconfig
View File

@ -279,6 +279,12 @@ CONFIG_BACKEND=file
# none = Empty template
#CONFIG_L2_PACKET=linux
# Disable Linux packet socket workaround applicable for station interface
# in a bridge for EAPOL frames. This should be uncommented only if the kernel
# is known to not have the regression issue in packet socket behavior with
# bridge interfaces (commit 'bridge: respect RFC2863 operational state')').
#CONFIG_NO_LINUX_PACKET_SOCKET_WAR=y
# PeerKey handshake for Station to Station Link (IEEE 802.11e DLS)
CONFIG_PEERKEY=y