libbpf: add function to setup XDP (949abbe8) · Commits · e / devices / android_kernel_fairphone_FP4

tools/lib/bpf/bpf.c

+122 −0

Original line number	Diff line number	Diff line
		@@ -25,6 +25,12 @@
		#include <asm/unistd.h>
		#include <linux/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
		@@ -46,7 +52,9 @@
		# endif
		#endif

		#ifndef min
		#define min(x, y) ((x) < (y) ? (x) : (y))
		#endif

		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)

		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;
		}

tools/lib/bpf/libbpf.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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)

tools/lib/bpf/libbpf.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -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