1 files changed, 170 insertions, 0 deletions
diff --git a/nhrpd/znl.c b/nhrpd/znl.c
new file mode 100644
index 0000000..6030987
--- /dev/null
+++ b/nhrpd/znl.c
@@ -0,0 +1,170 @@
+/* Netlink helpers for zbuf
+ * Copyright (c) 2014-2015 Timo Teräs
+ *
+ * This file is free software: you may copy, redistribute and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+
+#include "znl.h"
+
+#define ZNL_ALIGN(len)		(((len)+3) & ~3)
+
+void *znl_push(struct zbuf *zb, size_t n)
+{
+	return zbuf_pushn(zb, ZNL_ALIGN(n));
+}
+
+void *znl_pull(struct zbuf *zb, size_t n)
+{
+	return zbuf_pulln(zb, ZNL_ALIGN(n));
+}
+
+struct nlmsghdr *znl_nlmsg_push(struct zbuf *zb, uint16_t type, uint16_t flags)
+{
+	struct nlmsghdr *n;
+
+	n = znl_push(zb, sizeof(*n));
+	if (!n)
+		return NULL;
+
+	*n = (struct nlmsghdr){
+		.nlmsg_type = type, .nlmsg_flags = flags,
+	};
+	return n;
+}
+
+void znl_nlmsg_complete(struct zbuf *zb, struct nlmsghdr *n)
+{
+	n->nlmsg_len = zb->tail - (uint8_t *)n;
+}
+
+struct nlmsghdr *znl_nlmsg_pull(struct zbuf *zb, struct zbuf *payload)
+{
+	struct nlmsghdr *n;
+	size_t plen;
+
+	n = znl_pull(zb, sizeof(*n));
+	if (!n)
+		return NULL;
+
+	plen = n->nlmsg_len - sizeof(*n);
+	zbuf_init(payload, znl_pull(zb, plen), plen, plen);
+	zbuf_may_pulln(zb, ZNL_ALIGN(plen) - plen);
+
+	return n;
+}
+
+struct rtattr *znl_rta_push(struct zbuf *zb, uint16_t type, const void *val,
+			    size_t len)
+{
+	struct rtattr *rta;
+	uint8_t *dst;
+
+	rta = znl_push(zb, ZNL_ALIGN(sizeof(*rta)) + ZNL_ALIGN(len));
+	if (!rta)
+		return NULL;
+
+	*rta = (struct rtattr){
+		.rta_type = type, .rta_len = ZNL_ALIGN(sizeof(*rta)) + len,
+	};
+
+	dst = (uint8_t *)(rta + 1);
+	memcpy(dst, val, len);
+	memset(dst + len, 0, ZNL_ALIGN(len) - len);
+
+	return rta;
+}
+
+struct rtattr *znl_rta_push_u32(struct zbuf *zb, uint16_t type, uint32_t val)
+{
+	return znl_rta_push(zb, type, &val, sizeof(val));
+}
+
+struct rtattr *znl_rta_nested_push(struct zbuf *zb, uint16_t type)
+{
+	struct rtattr *rta;
+
+	rta = znl_push(zb, sizeof(*rta));
+	if (!rta)
+		return NULL;
+
+	*rta = (struct rtattr){
+		.rta_type = type,
+	};
+	return rta;
+}
+
+void znl_rta_nested_complete(struct zbuf *zb, struct rtattr *rta)
+{
+	size_t len = zb->tail - (uint8_t *)rta;
+	size_t align = ZNL_ALIGN(len) - len;
+
+	if (align) {
+		void *dst = zbuf_pushn(zb, align);
+		if (dst)
+			memset(dst, 0, align);
+	}
+	rta->rta_len = len;
+}
+
+struct rtattr *znl_rta_pull(struct zbuf *zb, struct zbuf *payload)
+{
+	struct rtattr *rta;
+	size_t plen;
+
+	rta = znl_pull(zb, sizeof(*rta));
+	if (!rta)
+		return NULL;
+
+	if (rta->rta_len > sizeof(*rta)) {
+		plen = rta->rta_len - sizeof(*rta);
+		zbuf_init(payload, znl_pull(zb, plen), plen, plen);
+	} else {
+		zbuf_init(payload, NULL, 0, 0);
+	}
+
+	return rta;
+}
+
+int znl_open(int protocol, int groups)
+{
+	struct sockaddr_nl addr;
+	int fd, buf = 128 * 1024;
+
+	fd = socket(AF_NETLINK, SOCK_RAW, protocol);
+	if (fd < 0)
+		return -1;
+
+	if (fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK) < 0)
+		goto error;
+	if (fcntl(fd, F_SETFD, FD_CLOEXEC) < 0)
+		goto error;
+	if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &buf, sizeof(buf)) < 0)
+		goto error;
+
+	memset(&addr, 0, sizeof(addr));
+	addr.nl_family = AF_NETLINK;
+	addr.nl_groups = groups;
+	if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0)
+		goto error;
+
+	return fd;
+error:
+	close(fd);
+	return -1;
+}