--- /dev/null
+/*
+ * VRRP ARP primitives.
+ *
+ * Copyright (C) 2001-2017 Alexandre Cassen
+ * Portions:
+ * Copyright (C) 2018 Cumulus Networks
+ * Quentin Young
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <zebra.h>
+
+#include <net/if_arp.h>
+#include <linux/if_packet.h>
+#include <netinet/if_ether.h>
+
+#include "lib/if.h"
+#include "lib/linklist.h"
+#include "lib/log.h"
+#include "lib/memory.h"
+#include "lib/prefix.h"
+
+#include "vrrp.h"
+#include "vrrp_arp.h"
+
+/*
+ * The size of the garp packet buffer should be the large enough to hold the
+ * largest arp packet to be sent + the size of the link layer header for the
+ * corresponding protocol. In this case we hardcode for Ethernet.
+ */
+#define GARP_BUFFER_SIZE \
+ sizeof(struct ether_header) + sizeof(struct arphdr) + 2 * ETH_ALEN \
+ + 2 * sizeof(struct in_addr)
+
+/* static vars */
+static int garp_fd = -1;
+
+/* Send the gratuitous ARP message */
+static ssize_t vrrp_send_garp(struct interface *ifp, uint8_t *buf, ssize_t pack_len)
+{
+ struct sockaddr_ll sll;
+ ssize_t len;
+
+ /* Build the dst device */
+ memset(&sll, 0, sizeof(sll));
+ sll.sll_family = AF_PACKET;
+ sll.sll_protocol = ETH_P_ARP;
+ sll.sll_ifindex = (int) ifp->ifindex;
+ sll.sll_halen = ifp->hw_addr_len;
+ memset(sll.sll_addr, 0xFF, ETH_ALEN);
+
+ /* Send packet */
+ len = sendto(garp_fd, buf, pack_len, 0, (struct sockaddr *)&sll,
+ sizeof(sll));
+
+ return len;
+}
+
+/* Build a gratuitous ARP message over a specific interface */
+static ssize_t vrrp_build_garp(uint8_t *buf, struct interface *ifp,
+ struct in_addr *v4)
+{
+ uint8_t *arp_ptr;
+
+ if (ifp->hw_addr_len == 0)
+ return -1;
+
+ /* Build Ethernet header */
+ struct ether_header *eth = (struct ether_header *) buf;
+
+ memset(eth->ether_dhost, 0xFF, ETH_ALEN);
+ memcpy(eth->ether_shost, ifp->hw_addr, ETH_ALEN);
+ eth->ether_type = htons(ETHERTYPE_ARP);
+
+ /* Build ARP payload */
+ struct arphdr *arph = (struct arphdr *) (buf + ETHER_HDR_LEN);
+
+ arph->ar_hrd = htons(HWTYPE_ETHER);
+ arph->ar_pro = htons(ETHERTYPE_IP);
+ arph->ar_hln = ifp->hw_addr_len;
+ arph->ar_pln = sizeof(struct in_addr);
+ arph->ar_op = htons(ARPOP_REQUEST);
+ arp_ptr = (uint8_t *)(arph + sizeof(struct arphdr));
+ /* Source MAC: us */
+ memcpy(arp_ptr, ifp->hw_addr, ifp->hw_addr_len);
+ arp_ptr += ifp->hw_addr_len;
+ /* Source IP: us */
+ memcpy(arp_ptr, &v4, sizeof(struct in_addr));
+ arp_ptr += sizeof(struct in_addr);
+ /* Dest MAC: broadcast */
+ memset(arp_ptr, 0xFF, ETH_ALEN);
+ arp_ptr += ifp->hw_addr_len;
+ /* Dest IP: us */
+ memcpy(arp_ptr, &v4, sizeof(struct in_addr));
+ arp_ptr += sizeof(struct in_addr);
+
+ return arp_ptr - buf;
+}
+
+void vrrp_garp_send(struct vrrp_vrouter *vr, struct in_addr *v4)
+{
+ struct interface *ifp = vr->ifp;
+ uint8_t garpbuf[GARP_BUFFER_SIZE];
+ ssize_t garpbuf_len;
+ ssize_t sent_len;
+ char astr[INET_ADDRSTRLEN];
+
+ /* If the interface doesn't support ARP, don't try sending */
+ if (ifp->flags & IFF_NOARP) {
+ zlog_warn(
+ "Unable to send gratuitous ARP on %s; has IFF_NOARP\n",
+ ifp->name);
+ return;
+ }
+
+ /* Build garp */
+ garpbuf_len = vrrp_build_garp(garpbuf, ifp, v4);
+
+ /* Send garp */
+ inet_ntop(AF_INET, v4, astr, sizeof(astr));
+ zlog_info("Sending gratuitous ARP on %s for %s", ifp->name, astr);
+ sent_len = vrrp_send_garp(ifp, garpbuf, garpbuf_len);
+
+ if (sent_len < 0)
+ zlog_warn("Error sending gratuitous ARP on %s for %s",
+ ifp->name, astr);
+}
+
+void vrrp_garp_send_all(struct vrrp_vrouter *vr)
+{
+ struct interface *ifp = vr->ifp;
+
+ /* If the interface doesn't support ARP, don't try sending */
+ if (ifp->flags & IFF_NOARP) {
+ zlog_warn(
+ "Unable to send gratuitous ARP on %s; has IFF_NOARP\n",
+ ifp->name);
+ return;
+ }
+
+ struct listnode *ln;
+ struct in_addr *v4;
+
+ for (ALL_LIST_ELEMENTS_RO(vr->v4, ln, v4))
+ vrrp_garp_send(vr, v4);
+}
+
+
+void vrrp_garp_init(void)
+{
+ /* Create the socket descriptor */
+ /* FIXME: why ETH_P_RARP? */
+ garp_fd = socket(PF_PACKET, SOCK_RAW | SOCK_CLOEXEC, htons(ETH_P_RARP));
+
+ if (garp_fd > 0)
+ zlog_info("Initialized gratuitous ARP socket");
+ else {
+ zlog_err("Error initializing gratuitous ARP socket");
+ return;
+ }
+}
+
+void vrrp_garp_fini(void)
+{
+ close(garp_fd);
+ garp_fd = -1;
+}
--- /dev/null
+/*
+ * VRRPD global definitions
+ * Copyright (C) 2018 Cumulus Networks, Inc.
+ * Quentin Young
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#ifndef _VRRP_ARP_H
+#define _VRRP_ARP_H
+
+#include <zebra.h>
+
+#include "vrrp.h"
+
+/* FIXME: Use the kernel define for this */
+#define HWTYPE_ETHER 1
+
+/* prototypes */
+extern void vrrp_garp_init(void);
+extern void vrrp_garp_fini(void);
+extern void vrrp_garp_send(struct vrrp_vrouter *vr, struct in_addr *v4);
+extern void vrrp_garp_send_all(struct vrrp_vrouter *vr);
+#endif
projects / mirror_frr.git / commitdiff