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vrrpd: cleanup vrrp packet crafting code
* Prefix all packet functions with 'vrrp_pkt' * Break out checksum computation into separate function * Accept version field when building advertisements * Update doc comments Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
This commit is contained in:
Quentin Young
parent
72df9d93a5
commit
d9e01e1cab
20
vrrpd/vrrp.c
20
vrrpd/vrrp.c
@ -424,18 +424,18 @@ static int vrrp_master_down_timer_expire(struct thread *thread);
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static void vrrp_send_advertisement(struct vrrp_router *r)
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{
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struct vrrp_pkt *pkt;
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ssize_t pktlen;
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ssize_t pktsz;
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struct ipaddr *addrs[r->addrs->count];
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union sockunion dest;
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list_to_array(r->addrs, (void **)addrs, r->addrs->count);
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pktlen = vrrp_pkt_build(&pkt, &r->src, r->vr->vrid, r->priority,
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r->vr->advertisement_interval, r->addrs->count,
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(struct ipaddr **)&addrs);
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pktsz = vrrp_pkt_adver_build(&pkt, &r->src, 3, r->vr->vrid, r->priority,
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r->vr->advertisement_interval,
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r->addrs->count, (struct ipaddr **)&addrs);
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if (pktlen > 0)
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zlog_hexdump(pkt, (size_t) pktlen);
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if (pktsz > 0)
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zlog_hexdump(pkt, (size_t) pktsz);
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else
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zlog_warn("Could not build VRRP packet");
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@ -443,7 +443,7 @@ static void vrrp_send_advertisement(struct vrrp_router *r)
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r->family == AF_INET ? VRRP_MCASTV4_GROUP_STR : VRRP_MCASTV6_GROUP_STR;
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str2sockunion(group, &dest);
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ssize_t sent = sendto(r->sock_tx, pkt, (size_t)pktlen, 0, &dest.sa,
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ssize_t sent = sendto(r->sock_tx, pkt, (size_t)pktsz, 0, &dest.sa,
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sockunion_sizeof(&dest));
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XFREE(MTYPE_VRRP_PKT, pkt);
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@ -469,7 +469,7 @@ static int vrrp_recv_advertisement(struct vrrp_router *r, struct vrrp_pkt *pkt,
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size_t pktsize)
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{
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char dumpbuf[BUFSIZ];
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vrrp_pkt_dump(dumpbuf, sizeof(dumpbuf), pkt);
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vrrp_pkt_adver_dump(dumpbuf, sizeof(dumpbuf), pkt);
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zlog_debug("Received VRRP Advertisement:\n%s", dumpbuf);
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/* Check that VRID matches our configured VRID */
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@ -595,8 +595,8 @@ static int vrrp_read(struct thread *thread)
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r->vr->vrid, family2str(r->family));
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zlog_hexdump(r->ibuf, nbytes);
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pktsize = vrrp_parse_datagram(r->family, &m, nbytes, &pkt, errbuf,
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sizeof(errbuf));
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pktsize = vrrp_pkt_parse_datagram(r->family, &m, nbytes, &pkt, errbuf,
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sizeof(errbuf));
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if (pktsize < 0) {
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zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID
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@ -51,17 +51,67 @@ const char *vrrp_packet_names[16] = {
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};
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/* clang-format on */
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ssize_t vrrp_pkt_build(struct vrrp_pkt **pkt, struct ipaddr *src, uint8_t vrid,
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uint8_t prio, uint16_t max_adver_int, uint8_t numip,
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struct ipaddr **ips)
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/*
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* Compute the VRRP checksum.
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*
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* Checksum is not set in the packet, just computed.
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*
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* pkt
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* VRRP packet, fully filled out except for checksum field.
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*
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* pktsize
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* sizeof(*pkt)
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*
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* src
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* IP address that pkt will be transmitted from.
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*
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* Returns:
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* VRRP checksum in network byte order.
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*/
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static uint16_t vrrp_pkt_checksum(struct vrrp_pkt *pkt, size_t pktsize,
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struct ipaddr *src)
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{
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uint16_t chksum;
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bool v6 = (src->ipa_type == IPADDR_V6);
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uint16_t chksum_pre = pkt->hdr.chksum;
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pkt->hdr.chksum = 0;
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if (v6) {
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struct ipv6_ph ph = {};
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ph.src = src->ipaddr_v6;
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inet_pton(AF_INET6, VRRP_MCASTV6_GROUP_STR, &ph.dst);
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ph.ulpl = htons(pktsize);
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ph.next_hdr = 112;
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chksum = in_cksum_with_ph6(&ph, pkt, pktsize);
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} else {
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struct ipv4_ph ph = {};
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ph.src = src->ipaddr_v4;
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inet_pton(AF_INET, VRRP_MCASTV4_GROUP_STR, &ph.dst);
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ph.proto = 112;
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ph.len = htons(pktsize);
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chksum = in_cksum_with_ph4(&ph, pkt, pktsize);
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}
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pkt->hdr.chksum = chksum_pre;
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return chksum;
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}
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ssize_t vrrp_pkt_adver_build(struct vrrp_pkt **pkt, struct ipaddr *src,
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uint8_t version, uint8_t vrid, uint8_t prio,
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uint16_t max_adver_int, uint8_t numip,
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struct ipaddr **ips)
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{
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assert(version >= 2 && version <= 3);
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bool v6 = IS_IPADDR_V6(ips[0]);
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size_t addrsz = v6 ? sizeof(struct in6_addr) : sizeof(struct in_addr);
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size_t pktsize = VRRP_PKT_SIZE(v6 ? AF_INET6 : AF_INET, numip);
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*pkt = XCALLOC(MTYPE_VRRP_PKT, pktsize);
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(*pkt)->hdr.vertype |= VRRP_VERSION << 4;
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(*pkt)->hdr.vertype |= version << 4;
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(*pkt)->hdr.vertype |= VRRP_TYPE_ADVERTISEMENT;
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(*pkt)->hdr.vrid = vrid;
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(*pkt)->hdr.priority = prio;
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@ -75,28 +125,12 @@ ssize_t vrrp_pkt_build(struct vrrp_pkt **pkt, struct ipaddr *src, uint8_t vrid,
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aptr += addrsz;
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}
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(*pkt)->hdr.chksum = 0;
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if (v6) {
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struct ipv6_ph ph = {};
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ph.src = src->ipaddr_v6;
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inet_pton(AF_INET6, VRRP_MCASTV6_GROUP_STR, &ph.dst);
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ph.ulpl = htons(pktsize);
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ph.next_hdr = 112;
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(*pkt)->hdr.chksum = in_cksum_with_ph6(&ph, *pkt, pktsize);
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} else {
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struct ipv4_ph ph = {};
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ph.src = src->ipaddr_v4;
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inet_pton(AF_INET, VRRP_MCASTV4_GROUP_STR, &ph.dst);
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ph.proto = 112;
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ph.len = htons(pktsize);
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(*pkt)->hdr.chksum = in_cksum_with_ph4(&ph, *pkt, pktsize);
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}
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(*pkt)->hdr.chksum = vrrp_pkt_checksum(*pkt, pktsize, src);
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return pktsize;
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}
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size_t vrrp_pkt_dump(char *buf, size_t buflen, struct vrrp_pkt *pkt)
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size_t vrrp_pkt_adver_dump(char *buf, size_t buflen, struct vrrp_pkt *pkt)
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{
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if (buflen < 1)
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return 0;
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@ -127,9 +161,9 @@ size_t vrrp_pkt_dump(char *buf, size_t buflen, struct vrrp_pkt *pkt)
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return rs;
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}
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ssize_t vrrp_parse_datagram(int family, struct msghdr *m, size_t read,
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struct vrrp_pkt **pkt, char *errmsg,
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size_t errmsg_len)
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ssize_t vrrp_pkt_parse_datagram(int family, struct msghdr *m, size_t read,
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struct vrrp_pkt **pkt, char *errmsg,
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size_t errmsg_len)
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{
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/* Source (MAC & IP), Dest (MAC & IP) TTL validation done by kernel */
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size_t addrsz = (family == AF_INET) ? sizeof(struct in_addr)
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@ -26,7 +26,6 @@
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#include "lib/memory.h"
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#include "lib/prefix.h"
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#define VRRP_VERSION 3
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#define VRRP_TYPE_ADVERTISEMENT 1
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extern const char *vrrp_packet_names[16];
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@ -94,11 +93,19 @@ struct vrrp_pkt {
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#define VRRP_MAX_PKT_SIZE VRRP_MAX_PKT_SIZE_V6
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/*
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* Builds a VRRP packet.
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* Builds a VRRP ADVERTISEMENT packet.
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*
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* pkt
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* Pointer to store pointer to result buffer in
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*
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* src
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* Source address packet will be transmitted from. This is needed to compute
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* the VRRP checksum. The returned packet must be sent in an IP datagram with
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* the source address equal to this field, or the checksum will be invalid.
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*
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* version
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* VRRP version; must be 2 or 3
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*
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* vrid
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* Virtual Router Identifier
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*
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@ -118,12 +125,13 @@ struct vrrp_pkt {
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* array of pointer to either struct in_addr (v6 = false) or struct in6_addr
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* (v6 = true)
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*/
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ssize_t vrrp_pkt_build(struct vrrp_pkt **pkt, struct ipaddr *src, uint8_t vrid,
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uint8_t prio, uint16_t max_adver_int, uint8_t numip,
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struct ipaddr **ips);
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ssize_t vrrp_pkt_adver_build(struct vrrp_pkt **pkt, struct ipaddr *src,
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uint8_t version, uint8_t vrid, uint8_t prio,
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uint16_t max_adver_int, uint8_t numip,
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struct ipaddr **ips);
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/*
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* Dumps a VRRP packet to a string.
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* Dumps a VRRP ADVERTISEMENT packet to a string.
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*
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* Currently only dumps the header.
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*
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@ -139,7 +147,7 @@ ssize_t vrrp_pkt_build(struct vrrp_pkt **pkt, struct ipaddr *src, uint8_t vrid,
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* Returns:
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* # bytes written to buf
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*/
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size_t vrrp_pkt_dump(char *buf, size_t buflen, struct vrrp_pkt *pkt);
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size_t vrrp_pkt_adver_dump(char *buf, size_t buflen, struct vrrp_pkt *pkt);
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/*
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@ -170,8 +178,8 @@ size_t vrrp_pkt_dump(char *buf, size_t buflen, struct vrrp_pkt *pkt);
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* Returns:
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* Size of VRRP packet, or -1 upon error
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*/
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ssize_t vrrp_parse_datagram(int family, struct msghdr *m, size_t read,
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struct vrrp_pkt **pkt, char *errmsg,
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size_t errmsg_len);
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ssize_t vrrp_pkt_parse_datagram(int family, struct msghdr *m, size_t read,
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struct vrrp_pkt **pkt, char *errmsg,
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size_t errmsg_len);
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#endif /* __VRRP_PACKET_H__ */
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