1 files changed, 314 insertions, 0 deletions
diff --git a/source3/lib/addrchange.c b/source3/lib/addrchange.c
new file mode 100644
index 0000000..9a64e8d
--- /dev/null
+++ b/source3/lib/addrchange.c
@@ -0,0 +1,314 @@
+/*
+ * Samba Unix/Linux SMB client library
+ * Copyright (C) Volker Lendecke 2011
+ *
+ * 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 "lib/addrchange.h"
+#include "../lib/util/tevent_ntstatus.h"
+
+#ifdef HAVE_LINUX_RTNETLINK_H
+
+#include "asm/types.h"
+#include "linux/netlink.h"
+#include "linux/rtnetlink.h"
+#include "lib/tsocket/tsocket.h"
+
+struct addrchange_context {
+	struct tdgram_context *sock;
+};
+
+NTSTATUS addrchange_context_create(TALLOC_CTX *mem_ctx,
+				   struct addrchange_context **pctx)
+{
+	struct addrchange_context *ctx;
+	struct sockaddr_nl addr;
+	NTSTATUS status;
+	int sock = -1;
+	int res;
+	bool ok;
+
+	ctx = talloc(mem_ctx, struct addrchange_context);
+	if (ctx == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+	if (sock == -1) {
+		status = map_nt_error_from_unix(errno);
+		goto fail;
+	}
+
+	ok = smb_set_close_on_exec(sock);
+	if (!ok) {
+		status = map_nt_error_from_unix(errno);
+		goto fail;
+	}
+
+	res = set_blocking(sock, false);
+	if (res == -1) {
+		status = map_nt_error_from_unix(errno);
+		goto fail;
+	}
+
+	/*
+	 * We're interested in address changes
+	 */
+	ZERO_STRUCT(addr);
+	addr.nl_family = AF_NETLINK;
+	addr.nl_groups = RTMGRP_IPV6_IFADDR | RTMGRP_IPV4_IFADDR;
+
+	res = bind(sock, (struct sockaddr *)(void *)&addr, sizeof(addr));
+	if (res == -1) {
+		status = map_nt_error_from_unix(errno);
+		goto fail;
+	}
+
+	res = tdgram_bsd_existing_socket(ctx, sock, &ctx->sock);
+	if (res == -1) {
+		status = map_nt_error_from_unix(errno);
+		goto fail;
+	}
+
+	*pctx = ctx;
+	return NT_STATUS_OK;
+fail:
+	if (sock != -1) {
+		close(sock);
+	}
+	TALLOC_FREE(ctx);
+	return status;
+}
+
+struct addrchange_state {
+	struct tevent_context *ev;
+	struct addrchange_context *ctx;
+	uint8_t *buf;
+	struct tsocket_address *fromaddr;
+
+	enum addrchange_type type;
+	struct sockaddr_storage addr;
+};
+
+static void addrchange_done(struct tevent_req *subreq);
+
+struct tevent_req *addrchange_send(TALLOC_CTX *mem_ctx,
+				   struct tevent_context *ev,
+				   struct addrchange_context *ctx)
+{
+	struct tevent_req *req, *subreq;
+	struct addrchange_state *state;
+
+	req = tevent_req_create(mem_ctx, &state, struct addrchange_state);
+	if (req == NULL) {
+		return NULL;
+	}
+	state->ev = ev;
+	state->ctx = ctx;
+
+	subreq = tdgram_recvfrom_send(state, state->ev, state->ctx->sock);
+	if (tevent_req_nomem(subreq, req)) {
+		return tevent_req_post(req, state->ev);
+	}
+	tevent_req_set_callback(subreq, addrchange_done, req);
+	return req;
+}
+
+static void addrchange_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+	struct addrchange_state *state = tevent_req_data(
+		req, struct addrchange_state);
+	union {
+		struct sockaddr sa;
+		struct sockaddr_nl nl;
+		struct sockaddr_storage ss;
+	} fromaddr;
+	struct nlmsghdr *h;
+	struct ifaddrmsg *ifa;
+	struct rtattr *rta;
+	ssize_t received;
+	int len;
+	int err;
+	bool found;
+
+	received = tdgram_recvfrom_recv(subreq, &err, state,
+					&state->buf,
+					&state->fromaddr);
+	TALLOC_FREE(subreq);
+	if (received == -1) {
+		DEBUG(10, ("tdgram_recvfrom_recv returned %s\n", strerror(err)));
+		tevent_req_nterror(req, map_nt_error_from_unix(err));
+		return;
+	}
+	len = tsocket_address_bsd_sockaddr(state->fromaddr,
+					   &fromaddr.sa,
+					   sizeof(fromaddr));
+
+	if ((len != sizeof(fromaddr.nl) ||
+	    fromaddr.sa.sa_family != AF_NETLINK))
+	{
+		DEBUG(10, ("Got message from wrong addr\n"));
+		goto retry;
+	}
+
+	if (fromaddr.nl.nl_pid != 0) {
+		DEBUG(10, ("Got msg from pid %d, not from the kernel\n",
+			   (int)fromaddr.nl.nl_pid));
+		goto retry;
+	}
+
+	if (received < sizeof(struct nlmsghdr)) {
+		DEBUG(10, ("received %d, expected at least %d\n",
+			   (int)received, (int)sizeof(struct nlmsghdr)));
+		goto retry;
+	}
+
+	h = (struct nlmsghdr *)state->buf;
+	if (h->nlmsg_len < sizeof(struct nlmsghdr)) {
+		DEBUG(10, ("nlmsg_len=%d, expected at least %d\n",
+			   (int)h->nlmsg_len, (int)sizeof(struct nlmsghdr)));
+		goto retry;
+	}
+	if (h->nlmsg_len > received) {
+		DEBUG(10, ("nlmsg_len=%d, expected at most %d\n",
+			   (int)h->nlmsg_len, (int)received));
+		goto retry;
+	}
+	switch (h->nlmsg_type) {
+	case RTM_NEWADDR:
+		state->type = ADDRCHANGE_ADD;
+		break;
+	case RTM_DELADDR:
+		state->type = ADDRCHANGE_DEL;
+		break;
+	default:
+		DEBUG(10, ("Got unexpected type %d - ignoring\n", h->nlmsg_type));
+		goto retry;
+	}
+
+	if (h->nlmsg_len < sizeof(struct nlmsghdr)+sizeof(struct ifaddrmsg)) {
+		DEBUG(10, ("nlmsg_len=%d, expected at least %d\n",
+			   (int)h->nlmsg_len,
+			   (int)(sizeof(struct nlmsghdr)
+				 +sizeof(struct ifaddrmsg))));
+		tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
+		return;
+	}
+
+	ifa = (struct ifaddrmsg *)NLMSG_DATA(h);
+
+	state->addr.ss_family = ifa->ifa_family;
+
+	len = h->nlmsg_len - sizeof(struct nlmsghdr) + sizeof(struct ifaddrmsg);
+
+	found = false;
+
+	for (rta = IFA_RTA(ifa); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
+
+		if ((rta->rta_type != IFA_LOCAL)
+		    && (rta->rta_type != IFA_ADDRESS)) {
+			continue;
+		}
+
+		switch (ifa->ifa_family) {
+		case AF_INET: {
+			struct sockaddr_in *v4_addr;
+			v4_addr = (struct sockaddr_in *)(void *)&state->addr;
+
+			if (RTA_PAYLOAD(rta) != sizeof(uint32_t)) {
+				continue;
+			}
+			v4_addr->sin_addr.s_addr = *(uint32_t *)RTA_DATA(rta);
+			found = true;
+			break;
+		}
+		case AF_INET6: {
+			struct sockaddr_in6 *v6_addr;
+			v6_addr = (struct sockaddr_in6 *)(void *)&state->addr;
+
+			if (RTA_PAYLOAD(rta) !=
+			    sizeof(v6_addr->sin6_addr.s6_addr)) {
+				continue;
+			}
+			memcpy(v6_addr->sin6_addr.s6_addr, RTA_DATA(rta),
+			       sizeof(v6_addr->sin6_addr.s6_addr));
+			found = true;
+			break;
+		}
+		}
+	}
+
+	if (!found) {
+		tevent_req_nterror(req, NT_STATUS_INVALID_ADDRESS);
+		return;
+	}
+
+	tevent_req_done(req);
+	return;
+
+retry:
+	TALLOC_FREE(state->buf);
+	TALLOC_FREE(state->fromaddr);
+
+	subreq = tdgram_recvfrom_send(state, state->ev, state->ctx->sock);
+	if (tevent_req_nomem(subreq, req)) {
+		return;
+	}
+	tevent_req_set_callback(subreq, addrchange_done, req);
+}
+
+NTSTATUS addrchange_recv(struct tevent_req *req, enum addrchange_type *type,
+			 struct sockaddr_storage *addr)
+{
+	struct addrchange_state *state = tevent_req_data(
+		req, struct addrchange_state);
+	NTSTATUS status;
+
+	if (tevent_req_is_nterror(req, &status)) {
+		tevent_req_received(req);
+		return status;
+	}
+
+	*type = state->type;
+	*addr = state->addr;
+	tevent_req_received(req);
+	return NT_STATUS_OK;
+}
+
+#else
+
+NTSTATUS addrchange_context_create(TALLOC_CTX *mem_ctx,
+				   struct addrchange_context **pctx)
+{
+	return NT_STATUS_NOT_SUPPORTED;
+}
+
+struct tevent_req *addrchange_send(TALLOC_CTX *mem_ctx,
+				   struct tevent_context *ev,
+				   struct addrchange_context *ctx)
+{
+	return NULL;
+}
+
+NTSTATUS addrchange_recv(struct tevent_req *req, enum addrchange_type *type,
+			 struct sockaddr_storage *addr)
+{
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+#endif