libbpf: Consistent prefixes for interfaces in libbpf.h.

libbpf is used more and more outside kernel tree. That means the library
should follow good practices in library design and implementation to
play well with third party code that uses it.

One of such practices is to have a common prefix (or a few) for every
interface, function or data structure, library provides. I helps to
avoid name conflicts with other libraries and keeps API consistent.

Inconsistent names in libbpf already cause problems in real life. E.g.
an application can't use both libbpf and libnl due to conflicting
symbols.

Having common prefix will help to fix current and avoid future problems.

libbpf already uses the following prefixes for its interfaces:
* bpf_ for bpf system call wrappers, program/map/elf-object
  abstractions and a few other things;
* btf_ for BTF related API;
* libbpf_ for everything else.

The patch adds libbpf_ prefix to functions and typedef in libbpf.h that
use none of mentioned above prefixes and doesn't fit well into the first
two categories.

Since affected part of API is used in bpftool, the patch applies
corresponding change to bpftool as well. Having it in a separate patch
will cause a state of tree where bpftool is broken what may not be a
good idea.

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/bpf/bpftool/net.c

@@ -127,14 +127,14 @@ static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
 	tcinfo.array_len = 0;
 
 	tcinfo.is_qdisc = false;
-	ret = nl_get_class(sock, nl_pid, dev->ifindex, dump_class_qdisc_nlmsg,
-			   &tcinfo);
+	ret = libbpf_nl_get_class(sock, nl_pid, dev->ifindex,
+				  dump_class_qdisc_nlmsg, &tcinfo);
 	if (ret)
 		goto out;
 
 	tcinfo.is_qdisc = true;
-	ret = nl_get_qdisc(sock, nl_pid, dev->ifindex, dump_class_qdisc_nlmsg,
-			   &tcinfo);
+	ret = libbpf_nl_get_qdisc(sock, nl_pid, dev->ifindex,
+				  dump_class_qdisc_nlmsg, &tcinfo);
 	if (ret)
 		goto out;
 
@@ -142,10 +142,9 @@ static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
 	filter_info.ifindex = dev->ifindex;
 	for (i = 0; i < tcinfo.used_len; i++) {
 		filter_info.kind = tcinfo.handle_array[i].kind;
-		ret = nl_get_filter(sock, nl_pid, dev->ifindex,
-				    tcinfo.handle_array[i].handle,
-				    dump_filter_nlmsg,
-				    &filter_info);
+		ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex,
+					   tcinfo.handle_array[i].handle,
+					   dump_filter_nlmsg, &filter_info);
 		if (ret)
 			goto out;
 	}
@@ -153,22 +152,22 @@ static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
 	/* root, ingress and egress handle */
 	handle = TC_H_ROOT;
 	filter_info.kind = "root";
-	ret = nl_get_filter(sock, nl_pid, dev->ifindex, handle,
-			    dump_filter_nlmsg, &filter_info);
+	ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
+				   dump_filter_nlmsg, &filter_info);
 	if (ret)
 		goto out;
 
 	handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
 	filter_info.kind = "clsact/ingress";
-	ret = nl_get_filter(sock, nl_pid, dev->ifindex, handle,
-			    dump_filter_nlmsg, &filter_info);
+	ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
+				   dump_filter_nlmsg, &filter_info);
 	if (ret)
 		goto out;
 
 	handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS);
 	filter_info.kind = "clsact/egress";
-	ret = nl_get_filter(sock, nl_pid, dev->ifindex, handle,
-			    dump_filter_nlmsg, &filter_info);
+	ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
+				   dump_filter_nlmsg, &filter_info);
 	if (ret)
 		goto out;
 
@@ -196,7 +195,7 @@ static int do_show(int argc, char **argv)
 		usage();
 	}
 
-	sock = bpf_netlink_open(&nl_pid);
+	sock = libbpf_netlink_open(&nl_pid);
 	if (sock < 0) {
 		fprintf(stderr, "failed to open netlink sock\n");
 		return -1;
@@ -211,7 +210,7 @@ static int do_show(int argc, char **argv)
 		jsonw_start_array(json_wtr);
 	NET_START_OBJECT;
 	NET_START_ARRAY("xdp", "%s:\n");
-	ret = nl_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
+	ret = libbpf_nl_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
 	NET_END_ARRAY("\n");
 
 	if (!ret) {

tools/lib/bpf/libbpf.h

@@ -305,14 +305,14 @@ int bpf_perf_event_read_simple(void *mem, unsigned long size,
 			       bpf_perf_event_print_t fn, void *priv);
 
 struct nlattr;
-typedef int (*dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
-int bpf_netlink_open(unsigned int *nl_pid);
-int nl_get_link(int sock, unsigned int nl_pid, dump_nlmsg_t dump_link_nlmsg,
-		void *cookie);
-int nl_get_class(int sock, unsigned int nl_pid, int ifindex,
-		 dump_nlmsg_t dump_class_nlmsg, void *cookie);
-int nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
-		 dump_nlmsg_t dump_qdisc_nlmsg, void *cookie);
-int nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
-		  dump_nlmsg_t dump_filter_nlmsg, void *cookie);
+typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
+int libbpf_netlink_open(unsigned int *nl_pid);
+int libbpf_nl_get_link(int sock, unsigned int nl_pid,
+		       libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie);
+int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex,
+			libbpf_dump_nlmsg_t dump_class_nlmsg, void *cookie);
+int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
+			libbpf_dump_nlmsg_t dump_qdisc_nlmsg, void *cookie);
+int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
+			 libbpf_dump_nlmsg_t dump_filter_nlmsg, void *cookie);
 #endif

tools/lib/bpf/netlink.c

@@ -18,10 +18,10 @@
 #define SOL_NETLINK 270
 #endif
 
-typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, dump_nlmsg_t,
+typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, libbpf_dump_nlmsg_t,
 			      void *cookie);
 
-int bpf_netlink_open(__u32 *nl_pid)
+int libbpf_netlink_open(__u32 *nl_pid)
 {
 	struct sockaddr_nl sa;
 	socklen_t addrlen;
@@ -65,7 +65,7 @@ cleanup:
 }
 
 static int bpf_netlink_recv(int sock, __u32 nl_pid, int seq,
-			    __dump_nlmsg_t _fn, dump_nlmsg_t fn,
+			    __dump_nlmsg_t _fn, libbpf_dump_nlmsg_t fn,
 			    void *cookie)
 {
 	bool multipart = true;
@@ -133,7 +133,7 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
 	} req;
 	__u32 nl_pid;
 
-	sock = bpf_netlink_open(&nl_pid);
+	sock = libbpf_netlink_open(&nl_pid);
 	if (sock < 0)
 		return sock;
 
@@ -181,8 +181,8 @@ cleanup:
 	return ret;
 }
 
-static int __dump_link_nlmsg(struct nlmsghdr *nlh, dump_nlmsg_t dump_link_nlmsg,
-			     void *cookie)
+static int __dump_link_nlmsg(struct nlmsghdr *nlh,
+			     libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie)
 {
 	struct nlattr *tb[IFLA_MAX + 1], *attr;
 	struct ifinfomsg *ifi = NLMSG_DATA(nlh);
@@ -196,8 +196,8 @@ static int __dump_link_nlmsg(struct nlmsghdr *nlh, dump_nlmsg_t dump_link_nlmsg,
 	return dump_link_nlmsg(cookie, ifi, tb);
 }
 
-int nl_get_link(int sock, unsigned int nl_pid, dump_nlmsg_t dump_link_nlmsg,
-		void *cookie)
+int libbpf_nl_get_link(int sock, unsigned int nl_pid,
+		       libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie)
 {
 	struct {
 		struct nlmsghdr nlh;
@@ -219,7 +219,8 @@ int nl_get_link(int sock, unsigned int nl_pid, dump_nlmsg_t dump_link_nlmsg,
 }
 
 static int __dump_class_nlmsg(struct nlmsghdr *nlh,
-			      dump_nlmsg_t dump_class_nlmsg, void *cookie)
+			      libbpf_dump_nlmsg_t dump_class_nlmsg,
+			      void *cookie)
 {
 	struct nlattr *tb[TCA_MAX + 1], *attr;
 	struct tcmsg *t = NLMSG_DATA(nlh);
@@ -233,8 +234,8 @@ static int __dump_class_nlmsg(struct nlmsghdr *nlh,
 	return dump_class_nlmsg(cookie, t, tb);
 }
 
-int nl_get_class(int sock, unsigned int nl_pid, int ifindex,
-		 dump_nlmsg_t dump_class_nlmsg, void *cookie)
+int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex,
+			libbpf_dump_nlmsg_t dump_class_nlmsg, void *cookie)
 {
 	struct {
 		struct nlmsghdr nlh;
@@ -257,7 +258,8 @@ int nl_get_class(int sock, unsigned int nl_pid, int ifindex,
 }
 
 static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh,
-			      dump_nlmsg_t dump_qdisc_nlmsg, void *cookie)
+			      libbpf_dump_nlmsg_t dump_qdisc_nlmsg,
+			      void *cookie)
 {
 	struct nlattr *tb[TCA_MAX + 1], *attr;
 	struct tcmsg *t = NLMSG_DATA(nlh);
@@ -271,8 +273,8 @@ static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh,
 	return dump_qdisc_nlmsg(cookie, t, tb);
 }
 
-int nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
-		 dump_nlmsg_t dump_qdisc_nlmsg, void *cookie)
+int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
+			libbpf_dump_nlmsg_t dump_qdisc_nlmsg, void *cookie)
 {
 	struct {
 		struct nlmsghdr nlh;
@@ -295,7 +297,8 @@ int nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
 }
 
 static int __dump_filter_nlmsg(struct nlmsghdr *nlh,
-			       dump_nlmsg_t dump_filter_nlmsg, void *cookie)
+			       libbpf_dump_nlmsg_t dump_filter_nlmsg,
+			       void *cookie)
 {
 	struct nlattr *tb[TCA_MAX + 1], *attr;
 	struct tcmsg *t = NLMSG_DATA(nlh);
@@ -309,8 +312,8 @@ static int __dump_filter_nlmsg(struct nlmsghdr *nlh,
 	return dump_filter_nlmsg(cookie, t, tb);
 }
 
-int nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
-		  dump_nlmsg_t dump_filter_nlmsg, void *cookie)
+int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
+			 libbpf_dump_nlmsg_t dump_filter_nlmsg, void *cookie)
 {
 	struct {
 		struct nlmsghdr nlh;