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Message-Id: <20171227180229.1926-2-eric@regit.org> Date: Wed, 27 Dec 2017 19:02:26 +0100 From: Eric Leblond <eric@...it.org> To: Alexei Starovoitov <alexei.starovoitov@...il.com> Cc: netdev@...r.kernel.org, daniel@...earbox.net, linux-kernel@...r.kernel.org, Eric Leblond <eric@...it.org> Subject: [PATCH 1/4] 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: Eric Leblond <eric@...it.org> --- tools/lib/bpf/bpf.c | 126 ++++++++++++++++++++++++++++++++++++++++++++++++- tools/lib/bpf/libbpf.c | 2 + tools/lib/bpf/libbpf.h | 4 ++ 3 files changed, 130 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 5128677e4117..1e3cfe6b9fce 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -25,6 +25,16 @@ #include <asm/unistd.h> #include <linux/bpf.h> #include "bpf.h" +#include "libbpf.h" +#include <linux/rtnetlink.h> +#include <sys/socket.h> +#include <errno.h> + +#ifndef IFLA_XDP_MAX +#define IFLA_XDP 43 +#define IFLA_XDP_FD 1 +#define IFLA_XDP_FLAGS 3 +#endif /* * When building perf, unistd.h is overridden. __NR_bpf is @@ -46,8 +56,6 @@ # endif #endif -#define min(x, y) ((x) < (y) ? (x) : (y)) - static inline __u64 ptr_to_u64(const void *ptr) { return (__u64) (unsigned long) ptr; @@ -413,3 +421,117 @@ int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len) 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 = errno; + 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; +} diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index e9c4b7cabcf2..5fe8aaa2123e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -106,6 +106,8 @@ static const char *libbpf_strerror_table[NR_ERRNO] = { [ERRCODE_OFFSET(PROG2BIG)] = "Program too big", [ERRCODE_OFFSET(KVER)] = "Incorrect kernel version", [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) diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 6e20003109e0..e42f96900318 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -42,6 +42,8 @@ enum libbpf_errno { LIBBPF_ERRNO__PROG2BIG, /* Program too big */ LIBBPF_ERRNO__KVER, /* Incorrect kernel version */ 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, }; @@ -246,4 +248,6 @@ long libbpf_get_error(const void *ptr); int bpf_prog_load(const char *file, enum bpf_prog_type type, struct bpf_object **pobj, int *prog_fd); + +int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags); #endif -- 2.15.1
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