Commit 949abbe8 authored by Eric Leblond's avatar Eric Leblond Committed by Alexei Starovoitov

libbpf: add function to setup XDP

Most of the code is taken from set_link_xdp_fd() in bpf_load.c and
slightly modified to be library compliant.
Signed-off-by: default avatarEric Leblond <eric@regit.org>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent dc2b9f19
...@@ -25,6 +25,12 @@ ...@@ -25,6 +25,12 @@
#include <asm/unistd.h> #include <asm/unistd.h>
#include <linux/bpf.h> #include <linux/bpf.h>
#include "bpf.h" #include "bpf.h"
#include "libbpf.h"
#include "nlattr.h"
#include <linux/rtnetlink.h>
#include <linux/if_link.h>
#include <sys/socket.h>
#include <errno.h>
/* /*
* When building perf, unistd.h is overridden. __NR_bpf is * When building perf, unistd.h is overridden. __NR_bpf is
...@@ -46,7 +52,9 @@ ...@@ -46,7 +52,9 @@
# endif # endif
#endif #endif
#ifndef min
#define min(x, y) ((x) < (y) ? (x) : (y)) #define min(x, y) ((x) < (y) ? (x) : (y))
#endif
static inline __u64 ptr_to_u64(const void *ptr) static inline __u64 ptr_to_u64(const void *ptr)
{ {
...@@ -413,3 +421,117 @@ int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len) ...@@ -413,3 +421,117 @@ int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len)
return err; return err;
} }
int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
{
struct sockaddr_nl sa;
int sock, seq = 0, len, ret = -1;
char buf[4096];
struct nlattr *nla, *nla_xdp;
struct {
struct nlmsghdr nh;
struct ifinfomsg ifinfo;
char attrbuf[64];
} req;
struct nlmsghdr *nh;
struct nlmsgerr *err;
socklen_t addrlen;
memset(&sa, 0, sizeof(sa));
sa.nl_family = AF_NETLINK;
sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock < 0) {
return -errno;
}
if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
ret = -errno;
goto cleanup;
}
addrlen = sizeof(sa);
if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) {
ret = -errno;
goto cleanup;
}
if (addrlen != sizeof(sa)) {
ret = -LIBBPF_ERRNO__INTERNAL;
goto cleanup;
}
memset(&req, 0, sizeof(req));
req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
req.nh.nlmsg_type = RTM_SETLINK;
req.nh.nlmsg_pid = 0;
req.nh.nlmsg_seq = ++seq;
req.ifinfo.ifi_family = AF_UNSPEC;
req.ifinfo.ifi_index = ifindex;
/* started nested attribute for XDP */
nla = (struct nlattr *)(((char *)&req)
+ NLMSG_ALIGN(req.nh.nlmsg_len));
nla->nla_type = NLA_F_NESTED | IFLA_XDP;
nla->nla_len = NLA_HDRLEN;
/* add XDP fd */
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));
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);
nla_xdp->nla_type = IFLA_XDP_FLAGS;
nla_xdp->nla_len = NLA_HDRLEN + sizeof(flags);
memcpy((char *)nla_xdp + NLA_HDRLEN, &flags, sizeof(flags));
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) {
ret = -errno;
goto cleanup;
}
len = recv(sock, buf, sizeof(buf), 0);
if (len < 0) {
ret = -errno;
goto cleanup;
}
for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
nh = NLMSG_NEXT(nh, len)) {
if (nh->nlmsg_pid != sa.nl_pid) {
ret = -LIBBPF_ERRNO__WRNGPID;
goto cleanup;
}
if (nh->nlmsg_seq != seq) {
ret = -LIBBPF_ERRNO__INVSEQ;
goto cleanup;
}
switch (nh->nlmsg_type) {
case NLMSG_ERROR:
err = (struct nlmsgerr *)NLMSG_DATA(nh);
if (!err->error)
continue;
ret = err->error;
goto cleanup;
case NLMSG_DONE:
break;
default:
break;
}
}
ret = 0;
cleanup:
close(sock);
return ret;
}
...@@ -106,6 +106,8 @@ static const char *libbpf_strerror_table[NR_ERRNO] = { ...@@ -106,6 +106,8 @@ static const char *libbpf_strerror_table[NR_ERRNO] = {
[ERRCODE_OFFSET(PROG2BIG)] = "Program too big", [ERRCODE_OFFSET(PROG2BIG)] = "Program too big",
[ERRCODE_OFFSET(KVER)] = "Incorrect kernel version", [ERRCODE_OFFSET(KVER)] = "Incorrect kernel version",
[ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type", [ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type",
[ERRCODE_OFFSET(WRNGPID)] = "Wrong pid in netlink message",
[ERRCODE_OFFSET(INVSEQ)] = "Invalid netlink sequence",
}; };
int libbpf_strerror(int err, char *buf, size_t size) int libbpf_strerror(int err, char *buf, size_t size)
......
...@@ -42,6 +42,8 @@ enum libbpf_errno { ...@@ -42,6 +42,8 @@ enum libbpf_errno {
LIBBPF_ERRNO__PROG2BIG, /* Program too big */ LIBBPF_ERRNO__PROG2BIG, /* Program too big */
LIBBPF_ERRNO__KVER, /* Incorrect kernel version */ LIBBPF_ERRNO__KVER, /* Incorrect kernel version */
LIBBPF_ERRNO__PROGTYPE, /* Kernel doesn't support this program type */ LIBBPF_ERRNO__PROGTYPE, /* Kernel doesn't support this program type */
LIBBPF_ERRNO__WRNGPID, /* Wrong pid in netlink message */
LIBBPF_ERRNO__INVSEQ, /* Invalid netlink sequence */
__LIBBPF_ERRNO__END, __LIBBPF_ERRNO__END,
}; };
...@@ -246,4 +248,6 @@ long libbpf_get_error(const void *ptr); ...@@ -246,4 +248,6 @@ long libbpf_get_error(const void *ptr);
int bpf_prog_load(const char *file, enum bpf_prog_type type, int bpf_prog_load(const char *file, enum bpf_prog_type type,
struct bpf_object **pobj, int *prog_fd); struct bpf_object **pobj, int *prog_fd);
int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
#endif #endif
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