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Date: Wed, 02 Oct 2019 15:30:33 +0200
From: Toke Høiland-Jørgensen <toke@...hat.com>
To: Daniel Borkmann <daniel@...earbox.net>
Cc: Alexei Starovoitov <ast@...nel.org>,
Martin KaFai Lau <kafai@...com>,
Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
Marek Majkowski <marek@...udflare.com>,
Lorenz Bauer <lmb@...udflare.com>,
David Miller <davem@...emloft.net>,
Jesper Dangaard Brouer <brouer@...hat.com>,
netdev@...r.kernel.org, bpf@...r.kernel.org
Subject: [PATCH bpf-next 8/9] libbpf: Add support for setting and getting XDP
chain maps
From: Toke Høiland-Jørgensen <toke@...hat.com>
This adds two new API functions for setting and getting XDP programs with
associated chain map IDs. Programs are expected to pair them, so that if a
program uses the chain map-aware setter, it should also use the associated
getter.
Programs using the old non-chain aware variants of the functions will not
set the XDP chain map attribute on the netlink message, resulting in the
kernel rejecting the command if a chain map has already been loaded.
Signed-off-by: Toke Høiland-Jørgensen <toke@...hat.com>
---
tools/lib/bpf/libbpf.h | 4 ++++
tools/lib/bpf/libbpf.map | 2 ++
tools/lib/bpf/netlink.c | 49 ++++++++++++++++++++++++++++++++++++++++++----
3 files changed, 51 insertions(+), 4 deletions(-)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index e8f70977d137..0a459840e32c 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -357,7 +357,11 @@ LIBBPF_API int bpf_prog_load(const char *file, enum bpf_prog_type type,
struct bpf_object **pobj, int *prog_fd);
LIBBPF_API int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
+LIBBPF_API int bpf_set_link_xdp_chain(int ifindex, int prog_fd, int chain_map_fd,
+ __u32 flags);
LIBBPF_API int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags);
+LIBBPF_API int bpf_get_link_xdp_chain(int ifindex, __u32 *prog_id, __u32 *chain_map_id,
+ __u32 flags);
struct perf_buffer;
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 8d10ca03d78d..59f412680292 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -192,4 +192,6 @@ LIBBPF_0.0.5 {
} LIBBPF_0.0.4;
LIBBPF_0.0.6 {
+ bpf_set_link_xdp_chain;
+ bpf_get_link_xdp_chain;
} LIBBPF_0.0.5;
diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
index ce3ec81b71c0..c6f63bdab2e6 100644
--- a/tools/lib/bpf/netlink.c
+++ b/tools/lib/bpf/netlink.c
@@ -25,6 +25,7 @@ struct xdp_id_md {
int ifindex;
__u32 flags;
__u32 id;
+ __u32 chain_map_id;
};
int libbpf_netlink_open(__u32 *nl_pid)
@@ -128,7 +129,8 @@ static int bpf_netlink_recv(int sock, __u32 nl_pid, int seq,
return ret;
}
-int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
+static int __bpf_set_link_xdp_fd(int ifindex, int *prog_fd, int *chain_map_fd,
+ __u32 flags)
{
int sock, seq = 0, ret;
struct nlattr *nla, *nla_xdp;
@@ -162,9 +164,19 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
nla_xdp->nla_type = IFLA_XDP_FD;
nla_xdp->nla_len = NLA_HDRLEN + sizeof(int);
- memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd));
+ memcpy((char *)nla_xdp + NLA_HDRLEN, prog_fd, sizeof(*prog_fd));
nla->nla_len += nla_xdp->nla_len;
+ if (chain_map_fd) {
+ /* add XDP chain map */
+ nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
+ nla_xdp->nla_type = IFLA_XDP_CHAIN_MAP_FD;
+ nla_xdp->nla_len = NLA_HDRLEN + sizeof(int);
+ memcpy((char *)nla_xdp + NLA_HDRLEN, chain_map_fd,
+ sizeof(*chain_map_fd));
+ nla->nla_len += nla_xdp->nla_len;
+ }
+
/* if user passed in any flags, add those too */
if (flags) {
nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
@@ -187,6 +199,17 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
return ret;
}
+int bpf_set_link_xdp_chain(int ifindex, int prog_fd, int chain_map_fd,
+ __u32 flags)
+{
+ return __bpf_set_link_xdp_fd(ifindex, &prog_fd, &chain_map_fd, flags);
+}
+
+int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
+{
+ return __bpf_set_link_xdp_fd(ifindex, &fd, NULL, flags);
+}
+
static int __dump_link_nlmsg(struct nlmsghdr *nlh,
libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie)
{
@@ -247,10 +270,13 @@ static int get_xdp_id(void *cookie, void *msg, struct nlattr **tb)
xdp_id->id = libbpf_nla_getattr_u32(xdp_tb[xdp_attr]);
+ if (xdp_tb[IFLA_XDP_CHAIN_MAP_ID])
+ xdp_id->chain_map_id = libbpf_nla_getattr_u32(xdp_tb[IFLA_XDP_CHAIN_MAP_ID]);
+
return 0;
}
-int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags)
+static int __bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 *chain_map_id, __u32 flags)
{
struct xdp_id_md xdp_id = {};
int sock, ret;
@@ -274,13 +300,28 @@ int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags)
xdp_id.flags = flags;
ret = libbpf_nl_get_link(sock, nl_pid, get_xdp_id, &xdp_id);
- if (!ret)
+ if (!ret) {
*prog_id = xdp_id.id;
+ if (chain_map_id)
+ *chain_map_id = xdp_id.chain_map_id;
+ }
+
close(sock);
return ret;
}
+int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags)
+{
+ return __bpf_get_link_xdp_id(ifindex, prog_id, NULL, flags);
+}
+
+int bpf_get_link_xdp_chain(int ifindex, __u32 *prog_id, __u32 *chain_map_id,
+ __u32 flags)
+{
+ return __bpf_get_link_xdp_id(ifindex, prog_id, chain_map_id, flags);
+}
+
int libbpf_nl_get_link(int sock, unsigned int nl_pid,
libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie)
{
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