e6dd8196e5
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. Since it does not look like this regression is going to get
fixed any time soon (it is already two years from that commit and over
1.5 from a discussion pointing out the regression), add a workaround in
wpa_supplicant to avoid this issue.
The wpa_supplicant workaround uses a secondary packet socket to capture
all frames (ETH_P_ALL) from the netdev that is in a bridge. This is
needed to avoid the kernel regression. However, this comes at the price
of more CPU load. Some of this is avoided with use of Linux socket
filter, but still, this is less efficient than a packet socket bound to
the specific EAPOL ethertype. The workaround gets disabled
automatically, if the main packet socket interface on the bridge
interface turns out to be working for RX (e.g., due to an old kernel
version being used or a new kernel version having a fix for the
regression). In addition, this workaround is only taken into use for the
special case of running wpa_supplicant with an interface in a bridge.
Signed-off-by: Jouni Malinen <j@w1.fi>
137 lines
2.9 KiB
C
137 lines
2.9 KiB
C
/*
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* WPA Supplicant - Layer2 packet handling example with dummy functions
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* Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
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*
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* This software may be distributed under the terms of the BSD license.
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* See README for more details.
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*
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* This file can be used as a starting point for layer2 packet implementation.
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*/
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#include "includes.h"
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#include "common.h"
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#include "eloop.h"
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#include "l2_packet.h"
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struct l2_packet_data {
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char ifname[17];
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u8 own_addr[ETH_ALEN];
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void (*rx_callback)(void *ctx, const u8 *src_addr,
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const u8 *buf, size_t len);
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void *rx_callback_ctx;
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int l2_hdr; /* whether to include layer 2 (Ethernet) header data
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* buffers */
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int fd;
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};
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int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
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{
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os_memcpy(addr, l2->own_addr, ETH_ALEN);
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return 0;
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}
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int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
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const u8 *buf, size_t len)
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{
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if (l2 == NULL)
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return -1;
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/*
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* TODO: Send frame (may need different implementation depending on
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* whether l2->l2_hdr is set).
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*/
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return 0;
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}
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static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
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{
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struct l2_packet_data *l2 = eloop_ctx;
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u8 buf[2300];
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int res;
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/* TODO: receive frame (e.g., recv() using sock */
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buf[0] = 0;
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res = 0;
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l2->rx_callback(l2->rx_callback_ctx, NULL /* TODO: src addr */,
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buf, res);
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}
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struct l2_packet_data * l2_packet_init(
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const char *ifname, const u8 *own_addr, unsigned short protocol,
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void (*rx_callback)(void *ctx, const u8 *src_addr,
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const u8 *buf, size_t len),
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void *rx_callback_ctx, int l2_hdr)
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{
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struct l2_packet_data *l2;
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l2 = os_zalloc(sizeof(struct l2_packet_data));
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if (l2 == NULL)
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return NULL;
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os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname));
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l2->rx_callback = rx_callback;
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l2->rx_callback_ctx = rx_callback_ctx;
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l2->l2_hdr = l2_hdr;
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/*
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* TODO: open connection for receiving frames
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*/
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l2->fd = -1;
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if (l2->fd >= 0)
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eloop_register_read_sock(l2->fd, l2_packet_receive, l2, NULL);
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return l2;
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}
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struct l2_packet_data * l2_packet_init_bridge(
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const char *br_ifname, const char *ifname, const u8 *own_addr,
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unsigned short protocol,
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void (*rx_callback)(void *ctx, const u8 *src_addr,
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const u8 *buf, size_t len),
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void *rx_callback_ctx, int l2_hdr)
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{
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return l2_packet_init(br_ifname, own_addr, protocol, rx_callback,
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rx_callback_ctx, l2_hdr);
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}
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void l2_packet_deinit(struct l2_packet_data *l2)
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{
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if (l2 == NULL)
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return;
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if (l2->fd >= 0) {
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eloop_unregister_read_sock(l2->fd);
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/* TODO: close connection */
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}
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os_free(l2);
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}
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int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
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{
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/* TODO: get interface IP address */
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return -1;
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}
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void l2_packet_notify_auth_start(struct l2_packet_data *l2)
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{
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/* This function can be left empty */
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}
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int l2_packet_set_packet_filter(struct l2_packet_data *l2,
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enum l2_packet_filter_type type)
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{
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return -1;
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}
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