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authorToke Høiland-Jørgensen <toke@redhat.com>2020-03-25 18:23:28 +0100
committerAlexei Starovoitov <ast@kernel.org>2020-03-28 14:24:41 -0700
commitbd5ca3ef93cd8fb7e913f15eeb78e67a0d802274 (patch)
tree20b66080e37c4e8fb4686963675ef38f6ef9c10d /tools/lib/bpf
parent50a3e678b58ae9535f9e536f2889649b624943c3 (diff)
libbpf: Add function to set link XDP fd while specifying old program
This adds a new function to set the XDP fd while specifying the FD of the program to replace, using the newly added IFLA_XDP_EXPECTED_FD netlink parameter. The new function uses the opts struct mechanism to be extendable in the future. Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/158515700857.92963.7052131201257841700.stgit@toke.dk
Diffstat (limited to 'tools/lib/bpf')
-rw-r--r--tools/lib/bpf/libbpf.h8
-rw-r--r--tools/lib/bpf/libbpf.map1
-rw-r--r--tools/lib/bpf/netlink.c34
3 files changed, 42 insertions, 1 deletions
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index d38d7a629417..bf7a35a9556d 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -444,7 +444,15 @@ struct xdp_link_info {
__u8 attach_mode;
};
+struct bpf_xdp_set_link_opts {
+ size_t sz;
+ __u32 old_fd;
+};
+#define bpf_xdp_set_link_opts__last_field old_fd
+
LIBBPF_API int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
+LIBBPF_API int bpf_set_link_xdp_fd_opts(int ifindex, int fd, __u32 flags,
+ const struct bpf_xdp_set_link_opts *opts);
LIBBPF_API int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags);
LIBBPF_API int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info,
size_t info_size, __u32 flags);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 5129283c0284..dcc87db3ca8a 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -244,4 +244,5 @@ LIBBPF_0.0.8 {
bpf_link__pin_path;
bpf_link__unpin;
bpf_program__set_attach_target;
+ bpf_set_link_xdp_fd_opts;
} LIBBPF_0.0.7;
diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
index 431bd25c6cdb..18b5319025e1 100644
--- a/tools/lib/bpf/netlink.c
+++ b/tools/lib/bpf/netlink.c
@@ -132,7 +132,8 @@ done:
return ret;
}
-int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
+static int __bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd,
+ __u32 flags)
{
int sock, seq = 0, ret;
struct nlattr *nla, *nla_xdp;
@@ -178,6 +179,14 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
nla->nla_len += nla_xdp->nla_len;
}
+ if (flags & XDP_FLAGS_REPLACE) {
+ nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
+ nla_xdp->nla_type = IFLA_XDP_EXPECTED_FD;
+ nla_xdp->nla_len = NLA_HDRLEN + sizeof(old_fd);
+ memcpy((char *)nla_xdp + NLA_HDRLEN, &old_fd, sizeof(old_fd));
+ nla->nla_len += nla_xdp->nla_len;
+ }
+
req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len);
if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) {
@@ -191,6 +200,29 @@ cleanup:
return ret;
}
+int bpf_set_link_xdp_fd_opts(int ifindex, int fd, __u32 flags,
+ const struct bpf_xdp_set_link_opts *opts)
+{
+ int old_fd = -1;
+
+ if (!OPTS_VALID(opts, bpf_xdp_set_link_opts))
+ return -EINVAL;
+
+ if (OPTS_HAS(opts, old_fd)) {
+ old_fd = OPTS_GET(opts, old_fd, -1);
+ flags |= XDP_FLAGS_REPLACE;
+ }
+
+ return __bpf_set_link_xdp_fd_replace(ifindex, fd,
+ old_fd,
+ flags);
+}
+
+int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
+{
+ return __bpf_set_link_xdp_fd_replace(ifindex, fd, 0, flags);
+}
+
static int __dump_link_nlmsg(struct nlmsghdr *nlh,
libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie)
{