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https://github.com/samba-team/samba.git
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ctdb-common: Factor out TCP packet marshalling code
This can be tested separately. Signed-off-by: Martin Schwenke <martin@meltin.net> Reviewed-by: Amitay Isaacs <amitay@gmail.com>
This commit is contained in:
Martin Schwenke
Amitay Isaacs
parent
a67899573a
commit
d7d23e78ed
@ -494,6 +494,121 @@ int ctdb_sys_send_arp(const ctdb_sock_addr *addr, const char *iface)
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#endif /* HAVE_PACKETSOCKET */
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#define IP4_TCP_BUFFER_SIZE sizeof(struct ip) + \
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sizeof(struct tcphdr)
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#define IP6_TCP_BUFFER_SIZE sizeof(struct ip6_hdr) + \
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sizeof(struct tcphdr)
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static int tcp4_build(uint8_t *buf,
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size_t buflen,
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const struct sockaddr_in *src,
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const struct sockaddr_in *dst,
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uint32_t seq,
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uint32_t ack,
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int rst,
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size_t *len)
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{
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size_t l = IP4_TCP_BUFFER_SIZE;
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struct {
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struct ip ip;
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struct tcphdr tcp;
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} *ip4pkt;
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if (l != sizeof(*ip4pkt)) {
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return EMSGSIZE;
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}
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if (buflen < l) {
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return EMSGSIZE;
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}
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ip4pkt = (void *)buf;
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memset(ip4pkt, 0, l);
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ip4pkt->ip.ip_v = 4;
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ip4pkt->ip.ip_hl = sizeof(ip4pkt->ip)/4;
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ip4pkt->ip.ip_len = htons(sizeof(ip4pkt));
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ip4pkt->ip.ip_ttl = 255;
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ip4pkt->ip.ip_p = IPPROTO_TCP;
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ip4pkt->ip.ip_src.s_addr = src->sin_addr.s_addr;
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ip4pkt->ip.ip_dst.s_addr = dst->sin_addr.s_addr;
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ip4pkt->ip.ip_sum = 0;
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ip4pkt->tcp.th_sport = src->sin_port;
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ip4pkt->tcp.th_dport = dst->sin_port;
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ip4pkt->tcp.th_seq = seq;
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ip4pkt->tcp.th_ack = ack;
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ip4pkt->tcp.th_flags = 0;
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ip4pkt->tcp.th_flags |= TH_ACK;
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if (rst) {
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ip4pkt->tcp.th_flags |= TH_RST;
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}
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ip4pkt->tcp.th_off = sizeof(ip4pkt->tcp)/4;
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/* this makes it easier to spot in a sniffer */
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ip4pkt->tcp.th_win = htons(1234);
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ip4pkt->tcp.th_sum = ip_checksum((uint16_t *)&ip4pkt->tcp,
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sizeof(ip4pkt->tcp),
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&ip4pkt->ip);
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*len = l;
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return 0;
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}
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static int tcp6_build(uint8_t *buf,
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size_t buflen,
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const struct sockaddr_in6 *src,
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const struct sockaddr_in6 *dst,
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uint32_t seq,
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uint32_t ack,
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int rst,
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size_t *len)
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{
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size_t l = IP6_TCP_BUFFER_SIZE;
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struct {
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struct ip6_hdr ip6;
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struct tcphdr tcp;
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} *ip6pkt;
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if (l != sizeof(*ip6pkt)) {
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return EMSGSIZE;
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}
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if (buflen < l) {
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return EMSGSIZE;
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}
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ip6pkt = (void *)buf;
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memset(ip6pkt, 0, l);
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ip6pkt->ip6.ip6_vfc = 0x60;
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ip6pkt->ip6.ip6_plen = htons(20);
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ip6pkt->ip6.ip6_nxt = IPPROTO_TCP;
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ip6pkt->ip6.ip6_hlim = 64;
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ip6pkt->ip6.ip6_src = src->sin6_addr;
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ip6pkt->ip6.ip6_dst = dst->sin6_addr;
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ip6pkt->tcp.th_sport = src->sin6_port;
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ip6pkt->tcp.th_dport = dst->sin6_port;
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ip6pkt->tcp.th_seq = seq;
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ip6pkt->tcp.th_ack = ack;
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ip6pkt->tcp.th_flags = 0;
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ip6pkt->tcp.th_flags |= TH_ACK;
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if (rst) {
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ip6pkt->tcp.th_flags |= TH_RST;
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}
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ip6pkt->tcp.th_off = sizeof(ip6pkt->tcp)/4;
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/* this makes it easier to spot in a sniffer */
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ip6pkt->tcp.th_win = htons(1234);
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ip6pkt->tcp.th_sum = ip6_checksum((uint16_t *)&ip6pkt->tcp,
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sizeof(ip6pkt->tcp),
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&ip6pkt->ip6);
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*len = l;
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return 0;
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}
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/*
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* Send tcp segment from the specified IP/port to the specified
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* destination IP/port.
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@ -511,48 +626,29 @@ int ctdb_sys_send_tcp(const ctdb_sock_addr *dest,
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uint32_t ack,
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int rst)
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{
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int s;
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uint8_t buf[MAX(IP4_TCP_BUFFER_SIZE, IP6_TCP_BUFFER_SIZE)];
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size_t len = 0;
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int ret;
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int s;
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uint32_t one = 1;
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uint16_t tmpport;
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ctdb_sock_addr *tmpdest;
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struct {
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struct ip ip;
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struct tcphdr tcp;
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} ip4pkt;
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struct {
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struct ip6_hdr ip6;
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struct tcphdr tcp;
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} ip6pkt;
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int saved_errno;
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switch (src->ip.sin_family) {
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case AF_INET:
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ZERO_STRUCT(ip4pkt);
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ip4pkt.ip.ip_v = 4;
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ip4pkt.ip.ip_hl = sizeof(ip4pkt.ip)/4;
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ip4pkt.ip.ip_len = htons(sizeof(ip4pkt));
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ip4pkt.ip.ip_ttl = 255;
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ip4pkt.ip.ip_p = IPPROTO_TCP;
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ip4pkt.ip.ip_src.s_addr = src->ip.sin_addr.s_addr;
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ip4pkt.ip.ip_dst.s_addr = dest->ip.sin_addr.s_addr;
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ip4pkt.ip.ip_sum = 0;
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ip4pkt.tcp.th_sport = src->ip.sin_port;
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ip4pkt.tcp.th_dport = dest->ip.sin_port;
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ip4pkt.tcp.th_seq = seq;
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ip4pkt.tcp.th_ack = ack;
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ip4pkt.tcp.th_flags = 0;
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ip4pkt.tcp.th_flags |= TH_ACK;
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if (rst) {
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ip4pkt.tcp.th_flags |= TH_RST;
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ret = tcp4_build(buf,
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sizeof(buf),
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&src->ip,
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&dest->ip,
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seq,
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ack,
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rst,
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&len);
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if (ret != 0) {
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DBG_ERR("Failed to build TCP packet (%d)\n", ret);
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return ret;
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}
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ip4pkt.tcp.th_off = sizeof(ip4pkt.tcp)/4;
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/* this makes it easier to spot in a sniffer */
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ip4pkt.tcp.th_win = htons(1234);
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ip4pkt.tcp.th_sum = ip_checksum((uint16_t *)&ip4pkt.tcp,
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sizeof(ip4pkt.tcp),
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&ip4pkt.ip);
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/* open a raw socket to send this segment from */
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s = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
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@ -570,40 +666,33 @@ int ctdb_sys_send_tcp(const ctdb_sock_addr *dest,
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return -1;
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}
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ret = sendto(s, &ip4pkt, sizeof(ip4pkt), 0,
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ret = sendto(s,
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buf,
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len,
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0,
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(const struct sockaddr *)&dest->ip,
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sizeof(dest->ip));
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saved_errno = errno;
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close(s);
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if (ret != sizeof(ip4pkt)) {
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if (ret != len) {
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D_ERR("Failed sendto (%s)\n", strerror(saved_errno));
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return -1;
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}
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break;
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case AF_INET6:
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ZERO_STRUCT(ip6pkt);
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ip6pkt.ip6.ip6_vfc = 0x60;
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ip6pkt.ip6.ip6_plen = htons(20);
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ip6pkt.ip6.ip6_nxt = IPPROTO_TCP;
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ip6pkt.ip6.ip6_hlim = 64;
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ip6pkt.ip6.ip6_src = src->ip6.sin6_addr;
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ip6pkt.ip6.ip6_dst = dest->ip6.sin6_addr;
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ip6pkt.tcp.th_sport = src->ip6.sin6_port;
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ip6pkt.tcp.th_dport = dest->ip6.sin6_port;
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ip6pkt.tcp.th_seq = seq;
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ip6pkt.tcp.th_ack = ack;
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ip6pkt.tcp.th_flags = 0;
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ip6pkt.tcp.th_flags |= TH_RST;
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if (rst) {
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ip6pkt.tcp.th_flags |= TH_RST;
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case AF_INET6:
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ret = tcp6_build(buf,
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sizeof(buf),
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&src->ip6,
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&dest->ip6,
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seq,
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ack,
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rst,
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&len);
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if (ret != 0) {
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DBG_ERR("Failed to build TCP packet (%d)\n", ret);
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return ret;
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}
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ip6pkt.tcp.th_off = sizeof(ip6pkt.tcp)/4;
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/* this makes it easier to spot in a sniffer */
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ip6pkt.tcp.th_win = htons(1234);
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ip6pkt.tcp.th_sum = ip6_checksum((uint16_t *)&ip6pkt.tcp,
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sizeof(ip6pkt.tcp),
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&ip6pkt.ip6);
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s = socket(AF_INET6, SOCK_RAW, IPPROTO_RAW);
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if (s == -1) {
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@ -618,14 +707,17 @@ int ctdb_sys_send_tcp(const ctdb_sock_addr *dest,
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tmpport = tmpdest->ip6.sin6_port;
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tmpdest->ip6.sin6_port = 0;
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ret = sendto(s, &ip6pkt, sizeof(ip6pkt), 0,
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ret = sendto(s,
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buf,
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len,
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0,
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(const struct sockaddr *)&dest->ip6,
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sizeof(dest->ip6));
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saved_errno = errno;
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tmpdest->ip6.sin6_port = tmpport;
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close(s);
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if (ret != sizeof(ip6pkt)) {
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if (ret != len) {
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D_ERR("Failed sendto (%s)\n", strerror(saved_errno));
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return -1;
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}
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