Merged the hostap_2.6 updates, and the Leap of Faith work, from the hostap_update...

[mech_eap.git] / libeap / src / ap / dhcp_snoop.c

diff --git a/libeap/src/ap/dhcp_snoop.c b/libeap/src/ap/dhcp_snoop.c
new file mode 100644 (file)
index 0000000..f0212fb
--- /dev/null
+++ b/libeap/src/ap/dhcp_snoop.c
@@ -0,0 +1,179 @@
+/*
+ * DHCP snooping for Proxy ARP
+ * Copyright (c) 2014, Qualcomm Atheros, Inc.
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#include "utils/includes.h"
+#include <netinet/ip.h>
+#include <netinet/udp.h>
+
+#include "utils/common.h"
+#include "l2_packet/l2_packet.h"
+#include "hostapd.h"
+#include "sta_info.h"
+#include "ap_drv_ops.h"
+#include "x_snoop.h"
+#include "dhcp_snoop.h"
+
+struct bootp_pkt {
+       struct iphdr iph;
+       struct udphdr udph;
+       u8 op;
+       u8 htype;
+       u8 hlen;
+       u8 hops;
+       be32 xid;
+       be16 secs;
+       be16 flags;
+       be32 client_ip;
+       be32 your_ip;
+       be32 server_ip;
+       be32 relay_ip;
+       u8 hw_addr[16];
+       u8 serv_name[64];
+       u8 boot_file[128];
+       u8 exten[312];
+} STRUCT_PACKED;
+
+#define DHCPACK        5
+static const u8 ic_bootp_cookie[] = { 99, 130, 83, 99 };
+
+
+static const char * ipaddr_str(u32 addr)
+{
+       static char buf[17];
+
+       os_snprintf(buf, sizeof(buf), "%u.%u.%u.%u",
+                   (addr >> 24) & 0xff, (addr >> 16) & 0xff,
+                   (addr >> 8) & 0xff, addr & 0xff);
+       return buf;
+}
+
+
+static void handle_dhcp(void *ctx, const u8 *src_addr, const u8 *buf,
+                       size_t len)
+{
+       struct hostapd_data *hapd = ctx;
+       const struct bootp_pkt *b;
+       struct sta_info *sta;
+       int exten_len;
+       const u8 *end, *pos;
+       int res, msgtype = 0, prefixlen = 32;
+       u32 subnet_mask = 0;
+       u16 tot_len;
+
+       exten_len = len - ETH_HLEN - (sizeof(*b) - sizeof(b->exten));
+       if (exten_len < 4)
+               return;
+
+       b = (const struct bootp_pkt *) &buf[ETH_HLEN];
+       tot_len = ntohs(b->iph.tot_len);
+       if (tot_len > (unsigned int) (len - ETH_HLEN))
+               return;
+
+       if (os_memcmp(b->exten, ic_bootp_cookie, ARRAY_SIZE(ic_bootp_cookie)))
+               return;
+
+       /* Parse DHCP options */
+       end = (const u8 *) b + tot_len;
+       pos = &b->exten[4];
+       while (pos < end && *pos != 0xff) {
+               const u8 *opt = pos++;
+
+               if (*opt == 0) /* padding */
+                       continue;
+
+               pos += *pos + 1;
+               if (pos >= end)
+                       break;
+
+               switch (*opt) {
+               case 1:  /* subnet mask */
+                       if (opt[1] == 4)
+                               subnet_mask = WPA_GET_BE32(&opt[2]);
+                       if (subnet_mask == 0)
+                               return;
+                       while (!(subnet_mask & 0x1)) {
+                               subnet_mask >>= 1;
+                               prefixlen--;
+                       }
+                       break;
+               case 53: /* message type */
+                       if (opt[1])
+                               msgtype = opt[2];
+                       break;
+               default:
+                       break;
+               }
+       }
+
+       if (msgtype == DHCPACK) {
+               if (b->your_ip == 0)
+                       return;
+
+               /* DHCPACK for DHCPREQUEST */
+               sta = ap_get_sta(hapd, b->hw_addr);
+               if (!sta)
+                       return;
+
+               wpa_printf(MSG_DEBUG, "dhcp_snoop: Found DHCPACK for " MACSTR
+                          " @ IPv4 address %s/%d",
+                          MAC2STR(sta->addr),
+                          ipaddr_str(be_to_host32(b->your_ip)),
+                          prefixlen);
+
+               if (sta->ipaddr == b->your_ip)
+                       return;
+
+               if (sta->ipaddr != 0) {
+                       wpa_printf(MSG_DEBUG,
+                                  "dhcp_snoop: Removing IPv4 address %s from the ip neigh table",
+                                  ipaddr_str(be_to_host32(sta->ipaddr)));
+                       hostapd_drv_br_delete_ip_neigh(hapd, 4,
+                                                      (u8 *) &sta->ipaddr);
+               }
+
+               res = hostapd_drv_br_add_ip_neigh(hapd, 4, (u8 *) &b->your_ip,
+                                                 prefixlen, sta->addr);
+               if (res) {
+                       wpa_printf(MSG_DEBUG,
+                                  "dhcp_snoop: Adding ip neigh table failed: %d",
+                                  res);
+                       return;
+               }
+               sta->ipaddr = b->your_ip;
+       }
+
+       if (hapd->conf->disable_dgaf && is_broadcast_ether_addr(buf)) {
+               for (sta = hapd->sta_list; sta; sta = sta->next) {
+                       if (!(sta->flags & WLAN_STA_AUTHORIZED))
+                               continue;
+                       x_snoop_mcast_to_ucast_convert_send(hapd, sta,
+                                                           (u8 *) buf, len);
+               }
+       }
+}
+
+
+int dhcp_snoop_init(struct hostapd_data *hapd)
+{
+       hapd->sock_dhcp = x_snoop_get_l2_packet(hapd, handle_dhcp,
+                                               L2_PACKET_FILTER_DHCP);
+       if (hapd->sock_dhcp == NULL) {
+               wpa_printf(MSG_DEBUG,
+                          "dhcp_snoop: Failed to initialize L2 packet processing for DHCP packet: %s",
+                          strerror(errno));
+               return -1;
+       }
+
+       return 0;
+}
+
+
+void dhcp_snoop_deinit(struct hostapd_data *hapd)
+{
+       l2_packet_deinit(hapd->sock_dhcp);
+}