r23806: update Samba4 with the latest ctdb code.

This doesn't get the ctdb code fully working in Samba4, it just gets
it building and not breaking non-clustered use of Samba. It will take
a bit longer to update some of the calling ctdb_cluster.c code to make
it work correctly in Samba4.

Note also that Samba4 now only links to the client portion of
ctdb. For the moment I am leaving the ctdbd as a separate daemon,
which you install separately from http://ctdb.samba.org/.
(This used to be commit b196077cbb55cbecad87065133c2d67198e31066)

1 files changed, 385 insertions, 0 deletions

diff --git a/source4/cluster/ctdb/common/system.c b/source4/cluster/ctdb/common/system.c
new file mode 100644
index 0000000000..1e536f5e8a
--- /dev/null
+++ b/source4/cluster/ctdb/common/system.c
@@ -0,0 +1,385 @@
+/* 
+   ctdb recovery code
+
+   Copyright (C) Ronnie Sahlberg  2007
+   Copyright (C) Andrew Tridgell  2007
+
+   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 3 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; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "system/network.h"
+#include "system/filesys.h"
+#include "system/wait.h"
+#include "../include/ctdb_private.h"
+#include "lib/events/events.h"
+#include <net/ethernet.h>
+#include <net/if_arp.h>
+
+
+
+/*
+  send gratuitous arp reply after we have taken over an ip address
+
+  saddr is the address we are trying to claim
+  iface is the interface name we will be using to claim the address
+ */
+int ctdb_sys_send_arp(const struct sockaddr_in *saddr, const char *iface)
+{
+	int s, ret;
+	struct sockaddr sa;
+	struct ether_header *eh;
+	struct arphdr *ah;
+	struct ifreq if_hwaddr;
+	unsigned char buffer[64]; /*minimum eth frame size */
+	char *ptr;
+
+	/* for now, we only handle AF_INET addresses */
+	if (saddr->sin_family != AF_INET) {
+		DEBUG(0,(__location__ " not an ipv4 address (family is %u)\n", saddr->sin_family));
+		return -1;
+	}
+
+	s = socket(AF_INET, SOCK_PACKET, htons(ETHERTYPE_ARP));
+	if (s == -1){
+		DEBUG(0,(__location__ " failed to open raw socket\n"));
+		return -1;
+	}
+
+	/* get the mac address */
+	strcpy(if_hwaddr.ifr_name, iface);
+	ret = ioctl(s, SIOCGIFHWADDR, &if_hwaddr);
+	if ( ret < 0 ) {
+		close(s);
+		DEBUG(0,(__location__ " ioctl failed\n"));
+		return -1;
+	}
+	if (ARPHRD_LOOPBACK == if_hwaddr.ifr_hwaddr.sa_family) {
+		DEBUG(3,("Ignoring loopback arp request\n"));
+		close(s);
+		return 0;
+	}
+	if (if_hwaddr.ifr_hwaddr.sa_family != AF_LOCAL) {
+		close(s);
+		errno = EINVAL;
+		DEBUG(0,(__location__ " not an ethernet address family (0x%x)\n",
+			 if_hwaddr.ifr_hwaddr.sa_family));
+		return -1;
+	}
+
+
+	memset(buffer, 0 , 64);
+	eh = (struct ether_header *)buffer;
+	memset(eh->ether_dhost, 0xff, ETH_ALEN);
+	memcpy(eh->ether_shost, if_hwaddr.ifr_hwaddr.sa_data, ETH_ALEN);
+	eh->ether_type = htons(ETHERTYPE_ARP);
+
+	ah = (struct arphdr *)&buffer[sizeof(struct ether_header)];
+	ah->ar_hrd = htons(ARPHRD_ETHER);
+	ah->ar_pro = htons(ETH_P_IP);
+	ah->ar_hln = ETH_ALEN;
+	ah->ar_pln = 4;
+
+	/* send a gratious arp */
+	ah->ar_op  = htons(ARPOP_REQUEST);
+	ptr = (char *)&ah[1];
+	memcpy(ptr, if_hwaddr.ifr_hwaddr.sa_data, ETH_ALEN);
+	ptr+=ETH_ALEN;
+	memcpy(ptr, &saddr->sin_addr, 4);	  
+	ptr+=4;
+	memset(ptr, 0, ETH_ALEN); 
+	ptr+=ETH_ALEN;
+	memcpy(ptr, &saddr->sin_addr, 4);	  
+	ptr+=4;
+
+	strncpy(sa.sa_data, iface, sizeof(sa.sa_data));
+	ret = sendto(s, buffer, 64, 0, &sa, sizeof(sa));
+	if (ret < 0 ){
+		close(s);
+		DEBUG(0,(__location__ " failed sendto\n"));
+		return -1;
+	}
+
+	/* send unsolicited arp reply broadcast */
+	ah->ar_op  = htons(ARPOP_REPLY);
+	ptr = (char *)&ah[1];
+	memcpy(ptr, if_hwaddr.ifr_hwaddr.sa_data, ETH_ALEN);
+	ptr+=ETH_ALEN;
+	memcpy(ptr, &saddr->sin_addr, 4);	  
+	ptr+=4;
+	memcpy(ptr, if_hwaddr.ifr_hwaddr.sa_data, ETH_ALEN);
+	ptr+=ETH_ALEN;
+	memcpy(ptr, &saddr->sin_addr, 4);	  
+	ptr+=4;
+
+	strncpy(sa.sa_data, iface, sizeof(sa.sa_data));
+	ret = sendto(s, buffer, 64, 0, &sa, sizeof(sa));
+	if (ret < 0 ){
+		DEBUG(0,(__location__ " failed sendto\n"));
+		return -1;
+	}
+
+	close(s);
+	return 0;
+}
+
+
+/*
+  uint16 checksum for n bytes
+ */
+static uint32_t uint16_checksum(uint16_t *data, size_t n)
+{
+	uint32_t sum=0;
+	while (n>=2) {
+		sum += (uint32_t)ntohs(*data);
+		data++;
+		n -= 2;
+	}
+	if (n == 1) {
+		sum += (uint32_t)ntohs(*(uint8_t *)data);
+	}
+	return sum;
+}
+
+/*
+  simple TCP checksum - assumes data is multiple of 2 bytes long
+ */
+static uint16_t tcp_checksum(uint16_t *data, size_t n, struct iphdr *ip)
+{
+	uint32_t sum = uint16_checksum(data, n);
+	uint16_t sum2;
+	sum += uint16_checksum((uint16_t *)&ip->saddr, sizeof(ip->saddr));
+	sum += uint16_checksum((uint16_t *)&ip->daddr, sizeof(ip->daddr));
+	sum += ip->protocol + n;
+	sum = (sum & 0xFFFF) + (sum >> 16);
+	sum = (sum & 0xFFFF) + (sum >> 16);
+	sum2 = htons(sum);
+	sum2 = ~sum2;
+	if (sum2 == 0) {
+		return 0xFFFF;
+	}
+	return sum2;
+}
+
+/*
+  Send tcp segment from the specified IP/port to the specified
+  destination IP/port. 
+
+  This is used to trigger the receiving host into sending its own ACK,
+  which should trigger early detection of TCP reset by the client
+  after IP takeover
+
+  This can also be used to send RST segments (if rst is true) and also
+  if correct seq and ack numbers are provided.
+ */
+int ctdb_sys_send_tcp(const struct sockaddr_in *dest, 
+		      const struct sockaddr_in *src,
+		      uint32_t seq, uint32_t ack, int rst)
+{
+	int s, ret;
+	uint32_t one = 1;
+	struct {
+		struct iphdr ip;
+		struct tcphdr tcp;
+	} pkt;
+
+	/* for now, we only handle AF_INET addresses */
+	if (src->sin_family != AF_INET || dest->sin_family != AF_INET) {
+		DEBUG(0,(__location__ " not an ipv4 address\n"));
+		return -1;
+	}
+
+	s = socket(AF_INET, SOCK_RAW, htons(IPPROTO_RAW));
+	if (s == -1) {
+		DEBUG(0,(__location__ " failed to open raw socket (%s)\n",
+			 strerror(errno)));
+		return -1;
+	}
+
+	ret = setsockopt(s, SOL_IP, IP_HDRINCL, &one, sizeof(one));
+	if (ret != 0) {
+		DEBUG(0,(__location__ " failed to setup IP headers (%s)\n",
+			 strerror(errno)));
+		close(s);
+		return -1;
+	}
+
+	ZERO_STRUCT(pkt);
+	pkt.ip.version  = 4;
+	pkt.ip.ihl      = sizeof(pkt.ip)/4;
+	pkt.ip.tot_len  = htons(sizeof(pkt));
+	pkt.ip.ttl      = 255;
+	pkt.ip.protocol = IPPROTO_TCP;
+	pkt.ip.saddr    = src->sin_addr.s_addr;
+	pkt.ip.daddr    = dest->sin_addr.s_addr;
+	pkt.ip.check    = 0;
+
+	pkt.tcp.source   = src->sin_port;
+	pkt.tcp.dest     = dest->sin_port;
+	pkt.tcp.seq      = seq;
+	pkt.tcp.ack_seq  = ack;
+	pkt.tcp.ack      = 1;
+	if (rst) {
+		pkt.tcp.rst      = 1;
+	}
+	pkt.tcp.doff     = sizeof(pkt.tcp)/4;
+	pkt.tcp.window   = htons(1234);
+	pkt.tcp.check    = tcp_checksum((uint16_t *)&pkt.tcp, sizeof(pkt.tcp), &pkt.ip);
+
+	ret = sendto(s, &pkt, sizeof(pkt), 0, dest, sizeof(*dest));
+	if (ret != sizeof(pkt)) {
+		DEBUG(0,(__location__ " failed sendto (%s)\n", strerror(errno)));
+		close(s);
+		return -1;
+	}
+
+	close(s);
+	return 0;
+}
+
+
+/*
+  see if we currently have an interface with the given IP
+
+  we try to bind to it, and if that fails then we don't have that IP
+  on an interface
+ */
+bool ctdb_sys_have_ip(const char *ip)
+{
+	struct sockaddr_in sin;
+	int s;
+	int ret;
+
+	sin.sin_port = 0;
+	inet_aton(ip, &sin.sin_addr);
+	sin.sin_family = AF_INET;
+	s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+	if (s == -1) {
+		return false;
+	}
+	ret = bind(s, (struct sockaddr *)&sin, sizeof(sin));
+	close(s);
+	return ret == 0;
+}
+
+static void ctdb_wait_handler(struct event_context *ev, struct timed_event *te, 
+			      struct timeval yt, void *p)
+{
+	uint32_t *timed_out = (uint32_t *)p;
+	(*timed_out) = 1;
+}
+
+/* This function is used to kill (RST) the specified tcp connection.
+
+   This function is not asynchronous and will block until the operation
+   was successful or it timesout.
+ */
+int ctdb_sys_kill_tcp(struct event_context *ev,
+		      const struct sockaddr_in *dst, 
+		      const struct sockaddr_in *src)
+{
+	int s, ret;
+	uint32_t timedout;
+	TALLOC_CTX *tmp_ctx = talloc_new(NULL);
+#define RCVPKTSIZE 100
+	char pkt[RCVPKTSIZE];
+	struct ether_header *eth;
+	struct iphdr *ip;
+	struct tcphdr *tcp;
+
+	/* Open a socket to capture all traffic */
+	s=socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
+	if (s == -1){
+		DEBUG(0,(__location__ " failed to open raw socket\n"));
+		return -1;
+	}
+
+	/* We wait for up to 1 second for the ACK coming back */
+	timedout = 0;
+	event_add_timed(ev, tmp_ctx, timeval_current_ofs(1, 0), ctdb_wait_handler, &timedout);
+
+	/* Send a tickle ack to probe what the real seq/ack numbers are */
+	ctdb_sys_send_tcp(dst, src, 0, 0, 0);
+
+	/* Wait until we either time out or we succeeds in sending the RST */
+	while (timedout==0) {
+		event_loop_once(ev);
+
+		ret = recv(s, pkt, RCVPKTSIZE, MSG_TRUNC);
+		if (ret < sizeof(*eth)+sizeof(*ip)) {
+			continue;
+		}
+
+		/* Ethernet */
+		eth = (struct ether_header *)pkt;
+		/* We only want IP packets */
+		if (ntohs(eth->ether_type) != ETHERTYPE_IP) {
+			continue;
+		}
+	
+		/* IP */
+		ip = (struct iphdr *)(eth+1);
+		/* We only want IPv4 packets */
+		if (ip->version != 4) {
+			continue;
+		}
+		/* Dont look at fragments */
+		if ((ntohs(ip->frag_off)&0x1fff) != 0) {
+			continue;
+		}
+		/* we only want TCP */
+		if (ip->protocol != IPPROTO_TCP) {
+			continue;
+		}
+
+		/* We only want packets sent from the guy we tickled */
+		if (ip->saddr != dst->sin_addr.s_addr) {
+			continue;
+		}
+		/* We only want packets sent to us */
+		if (ip->daddr != src->sin_addr.s_addr) {
+			continue;
+		}
+
+		/* make sure its not a short packet */
+		if (offsetof(struct tcphdr, ack_seq) + 4 + 
+		    (ip->ihl*4) + sizeof(*eth) > ret) {
+			continue;
+		}
+
+		/* TCP */
+		tcp = (struct tcphdr *)((ip->ihl*4) + (char *)ip);
+		
+		/* We only want replies from the port we tickled */
+		if (tcp->source != dst->sin_port) {
+			continue;
+		}
+		if (tcp->dest != src->sin_port) {
+			continue;
+		}
+
+		ctdb_sys_send_tcp(dst, src, tcp->ack_seq, tcp->seq, 1);
+
+		close(s);
+		talloc_free(tmp_ctx);
+
+		return 0;
+	}
+
+	close(s);
+	talloc_free(tmp_ctx);
+	DEBUG(0,(__location__ " timedout waiting for tickle ack reply\n"));
+
+	return -1;
+}