GNU/Hurd support

CTDB has the following limitations on GNU Hurd:

- The pid of a peer is not get from the socket [1]. As a consequence, the peer
  process is not killed when releasing IP [2].

- Gratuitous arp are not yet supported [3]

- network interfaces are always considered present [4]

[1]: ctdb_get_peer_pid() in common/system_gnu.c
[2]: release_kill_clients() in server/ctdb_takeover.c
[3]: ctdb_sys_send_arp() in common/system_gnu.c
[4]: ctdb_sys_check_iface_exists() in common/system_gnu.c

(This used to be ctdb commit 00212e5c7dd229e7f8975a165d5ab8875d4917cc)

1 files changed, 364 insertions, 0 deletions

diff --git a/ctdb/common/system_gnu.c b/ctdb/common/system_gnu.c
new file mode 100644
index 00000000000..604bb4828f1
--- /dev/null
+++ b/ctdb/common/system_gnu.c
@@ -0,0 +1,364 @@
+/* 
+   ctdb system specific code to manage raw sockets on linux
+
+   Copyright (C) Ronnie Sahlberg  2007
+   Copyright (C) Andrew Tridgell  2007
+   Copyright (C) Marc Dequènes (Duck) 2009
+
+   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/>.
+
+
+  This file is a copy of 'common/system_linux.c' adapted for Hurd needs,
+  and inspired by 'common/system_aix.c' for the pcap usage.
+*/
+
+#include "includes.h"
+#include "system/network.h"
+#include "system/filesys.h"
+#include "system/wait.h"
+#include "../include/ctdb_private.h"
+#include "lib/tevent/tevent.h"
+#include <net/ethernet.h>
+#include <netinet/ip6.h>
+#include <net/if_arp.h>
+#include <pcap.h>
+
+
+#ifndef ETHERTYPE_IP6
+#define ETHERTYPE_IP6 0x86dd
+#endif
+
+/*
+  calculate the tcp checksum for tcp over ipv6
+*/
+static uint16_t tcp_checksum6(uint16_t *data, size_t n, struct ip6_hdr *ip6)
+{
+	uint32_t phdr[2];
+	uint32_t sum = 0;
+	uint16_t sum2;
+
+	sum += uint16_checksum((uint16_t *)(void *)&ip6->ip6_src, 16);
+	sum += uint16_checksum((uint16_t *)(void *)&ip6->ip6_dst, 16);
+
+	phdr[0] = htonl(n);
+	phdr[1] = htonl(ip6->ip6_nxt);
+	sum += uint16_checksum((uint16_t *)phdr, 8);
+
+	sum += uint16_checksum(data, n);
+
+	sum = (sum & 0xFFFF) + (sum >> 16);
+	sum = (sum & 0xFFFF) + (sum >> 16);
+	sum2 = htons(sum);
+	sum2 = ~sum2;
+	if (sum2 == 0) {
+		return 0xFFFF;
+	}
+	return sum2;
+}
+
+/*
+  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 ctdb_sock_addr *addr, const char *iface)
+{
+	/* FIXME We dont do gratuitous arp on Hurd yet */
+	return 0;
+}
+
+
+/*
+  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 *)(void *)&ip->saddr,
+			       sizeof(ip->saddr));
+	sum += uint16_checksum((uint16_t *)(void *)&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 ctdb_sock_addr *dest, 
+		      const ctdb_sock_addr *src,
+		      uint32_t seq, uint32_t ack, int rst)
+{
+	int s;
+	int ret;
+	uint32_t one = 1;
+	uint16_t tmpport;
+	ctdb_sock_addr *tmpdest;
+	struct {
+		struct iphdr ip;
+		struct tcphdr tcp;
+	} ip4pkt;
+	struct {
+		struct ip6_hdr ip6;
+		struct tcphdr tcp;
+	} ip6pkt;
+
+	switch (src->ip.sin_family) {
+	case AF_INET:
+		ZERO_STRUCT(ip4pkt);
+		ip4pkt.ip.version  = 4;
+		ip4pkt.ip.ihl      = sizeof(ip4pkt.ip)/4;
+		ip4pkt.ip.tot_len  = htons(sizeof(ip4pkt));
+		ip4pkt.ip.ttl      = 255;
+		ip4pkt.ip.protocol = IPPROTO_TCP;
+		ip4pkt.ip.saddr    = src->ip.sin_addr.s_addr;
+		ip4pkt.ip.daddr    = dest->ip.sin_addr.s_addr;
+		ip4pkt.ip.check    = 0;
+
+		ip4pkt.tcp.source   = src->ip.sin_port;
+		ip4pkt.tcp.dest     = dest->ip.sin_port;
+		ip4pkt.tcp.seq      = seq;
+		ip4pkt.tcp.ack_seq  = ack;
+		ip4pkt.tcp.ack      = 1;
+		if (rst) {
+			ip4pkt.tcp.rst      = 1;
+		}
+		ip4pkt.tcp.doff     = sizeof(ip4pkt.tcp)/4;
+		/* this makes it easier to spot in a sniffer */
+		ip4pkt.tcp.window   = htons(1234);
+		ip4pkt.tcp.check    = tcp_checksum((uint16_t *)&ip4pkt.tcp, sizeof(ip4pkt.tcp), &ip4pkt.ip);
+
+		/* open a raw socket to send this segment from */
+		s = socket(AF_INET, SOCK_RAW, htons(IPPROTO_RAW));
+		if (s == -1) {
+			DEBUG(DEBUG_CRIT,(__location__ " failed to open raw socket (%s)\n",
+				 strerror(errno)));
+			return -1;
+		}
+
+		ret = setsockopt(s, IPPROTO_IP, IP_HDRINCL, &one, sizeof(one));
+		if (ret != 0) {
+			DEBUG(DEBUG_CRIT,(__location__ " failed to setup IP headers (%s)\n",
+				 strerror(errno)));
+			close(s);
+			return -1;
+		}
+
+		set_nonblocking(s);
+		set_close_on_exec(s);
+
+		ret = sendto(s, &ip4pkt, sizeof(ip4pkt), 0, &dest->ip, sizeof(dest->ip));
+		close(s);
+		if (ret != sizeof(ip4pkt)) {
+			DEBUG(DEBUG_CRIT,(__location__ " failed sendto (%s)\n", strerror(errno)));
+			return -1;
+		}
+		break;
+	case AF_INET6:
+		ZERO_STRUCT(ip6pkt);
+		ip6pkt.ip6.ip6_vfc  = 0x60;
+		ip6pkt.ip6.ip6_plen = htons(20);
+		ip6pkt.ip6.ip6_nxt  = IPPROTO_TCP;
+		ip6pkt.ip6.ip6_hlim = 64;
+		ip6pkt.ip6.ip6_src  = src->ip6.sin6_addr;
+		ip6pkt.ip6.ip6_dst  = dest->ip6.sin6_addr;
+
+		ip6pkt.tcp.source   = src->ip6.sin6_port;
+		ip6pkt.tcp.dest     = dest->ip6.sin6_port;
+		ip6pkt.tcp.seq      = seq;
+		ip6pkt.tcp.ack_seq  = ack;
+		ip6pkt.tcp.ack      = 1;
+		if (rst) {
+			ip6pkt.tcp.rst      = 1;
+		}
+		ip6pkt.tcp.doff     = sizeof(ip6pkt.tcp)/4;
+		/* this makes it easier to spot in a sniffer */
+		ip6pkt.tcp.window   = htons(1234);
+		ip6pkt.tcp.check    = tcp_checksum6((uint16_t *)&ip6pkt.tcp, sizeof(ip6pkt.tcp), &ip6pkt.ip6);
+
+		s = socket(PF_INET6, SOCK_RAW, IPPROTO_RAW);
+		if (s == -1) {
+			DEBUG(DEBUG_CRIT, (__location__ " Failed to open sending socket\n"));
+			return -1;
+
+		}
+		/* sendto() dont like if the port is set and the socket is
+		   in raw mode.
+		*/
+		tmpdest = discard_const(dest);
+		tmpport = tmpdest->ip6.sin6_port;
+
+		tmpdest->ip6.sin6_port = 0;
+		ret = sendto(s, &ip6pkt, sizeof(ip6pkt), 0, &dest->ip6, sizeof(dest->ip6));
+		tmpdest->ip6.sin6_port = tmpport;
+		close(s);
+
+		if (ret != sizeof(ip6pkt)) {
+			DEBUG(DEBUG_CRIT,(__location__ " failed sendto (%s)\n", strerror(errno)));
+			return -1;
+		}
+		break;
+
+	default:
+		DEBUG(DEBUG_CRIT,(__location__ " not an ipv4/v6 address\n"));
+		return -1;
+	}
+
+	return 0;
+}
+
+/* 
+   This function is used to open a raw socket to capture from
+ */
+int ctdb_sys_open_capture_socket(const char *iface, void **private_data)
+{
+	pcap_t *pt;
+
+	pt=pcap_open_live(iface, 100, 0, 0, NULL);
+	if (pt == NULL) {
+		DEBUG(DEBUG_CRIT,("Failed to open capture device %s\n", iface));
+		return -1;
+	}
+	*((pcap_t **)private_data) = pt;
+
+	return pcap_fileno(pt);
+}
+
+/* This function is used to close the capture socket
+ */
+int ctdb_sys_close_capture_socket(void *private_data)
+{
+	pcap_t *pt = (pcap_t *)private_data;
+	pcap_close(pt);
+	return 0;
+}
+
+
+/*
+  called when the raw socket becomes readable
+ */
+int ctdb_sys_read_tcp_packet(int s, void *private_data, 
+			ctdb_sock_addr *src, ctdb_sock_addr *dst,
+			uint32_t *ack_seq, uint32_t *seq)
+{
+	int ret;
+#define RCVPKTSIZE 100
+	char pkt[RCVPKTSIZE];
+	struct ether_header *eth;
+	struct iphdr *ip;
+	struct ip6_hdr *ip6;
+	struct tcphdr *tcp;
+
+	ret = recv(s, pkt, RCVPKTSIZE, MSG_TRUNC);
+	if (ret < sizeof(*eth)+sizeof(*ip)) {
+		return -1;
+	}
+
+	/* Ethernet */
+	eth = (struct ether_header *)pkt;
+
+	/* we want either IPv4 or IPv6 */
+	if (ntohs(eth->ether_type) == ETHERTYPE_IP) {
+		/* IP */
+		ip = (struct iphdr *)(eth+1);
+
+		/* We only want IPv4 packets */
+		if (ip->version != 4) {
+			return -1;
+		}
+		/* Dont look at fragments */
+		if ((ntohs(ip->frag_off)&0x1fff) != 0) {
+			return -1;
+		}
+		/* we only want TCP */
+		if (ip->protocol != IPPROTO_TCP) {
+			return -1;
+		}
+
+		/* make sure its not a short packet */
+		if (offsetof(struct tcphdr, ack_seq) + 4 + 
+		    (ip->ihl*4) + sizeof(*eth) > ret) {
+			return -1;
+		}
+		/* TCP */
+		tcp = (struct tcphdr *)((ip->ihl*4) + (char *)ip);
+
+		/* tell the caller which one we've found */
+		src->ip.sin_family      = AF_INET;
+		src->ip.sin_addr.s_addr = ip->saddr;
+		src->ip.sin_port        = tcp->source;
+		dst->ip.sin_family      = AF_INET;
+		dst->ip.sin_addr.s_addr = ip->daddr;
+		dst->ip.sin_port        = tcp->dest;
+		*ack_seq                = tcp->ack_seq;
+		*seq                    = tcp->seq;
+
+		return 0;
+	} else if (ntohs(eth->ether_type) == ETHERTYPE_IP6) {
+		/* IP6 */
+		ip6 = (struct ip6_hdr *)(eth+1);
+
+		/* we only want TCP */
+		if (ip6->ip6_nxt != IPPROTO_TCP) {
+			return -1;
+		}
+
+		/* TCP */
+		tcp = (struct tcphdr *)(ip6+1);
+
+		/* tell the caller which one we've found */
+		src->ip6.sin6_family = AF_INET6;
+		src->ip6.sin6_port   = tcp->source;
+		src->ip6.sin6_addr   = ip6->ip6_src;
+
+		dst->ip6.sin6_family = AF_INET6;
+		dst->ip6.sin6_port   = tcp->dest;
+		dst->ip6.sin6_addr   = ip6->ip6_dst;
+
+		*ack_seq             = tcp->ack_seq;
+		*seq                 = tcp->seq;
+
+		return 0;
+	}
+
+	return -1;
+}
+
+bool ctdb_sys_check_iface_exists(const char *iface)
+{
+	return true;
+}
+
+int ctdb_get_peer_pid(const int fd, pid_t *peer_pid)
+{
+	/* FIXME not implemented */
+	return 1;
+}