Helper program. Loads eBPF RSS program and maps and passes them through unix socket. Libvirt may launch this helper and pass eBPF fds to qemu virtio-net.
Signed-off-by: Andrew Melnychenko <and...@daynix.com> --- ebpf/qemu-ebpf-rss-helper.c | 130 ++++++++++++++++++++++++++++++++++++ meson.build | 8 +++ 2 files changed, 138 insertions(+) create mode 100644 ebpf/qemu-ebpf-rss-helper.c diff --git a/ebpf/qemu-ebpf-rss-helper.c b/ebpf/qemu-ebpf-rss-helper.c new file mode 100644 index 0000000000..f0379dddf2 --- /dev/null +++ b/ebpf/qemu-ebpf-rss-helper.c @@ -0,0 +1,130 @@ +/* + * eBPF RSS Helper + * + * Developed by Daynix Computing LTD (http://www.daynix.com) + * + * Authors: + * Andrew Melnychenko <and...@daynix.com> + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + * Description: This is helper program for libvirtd. + * It loads eBPF RSS program and passes fds through unix socket. + * Built by meson, target - 'qemu-ebpf-rss-helper'. + */ + +#include <stdio.h> +#include <stdint.h> +#include <stdlib.h> +#include <stdbool.h> +#include <getopt.h> +#include <memory.h> +#include <errno.h> +#include <sys/socket.h> + +#include "ebpf_rss.h" + +static int send_fds(int socket, int *fds, int n) +{ + struct msghdr msg = {}; + struct cmsghdr *cmsg = NULL; + char buf[CMSG_SPACE(n * sizeof(int))]; + char dummy_buffer = 0; + struct iovec io = { .iov_base = &dummy_buffer, + .iov_len = sizeof(dummy_buffer) }; + + memset(buf, 0, sizeof(buf)); + + msg.msg_iov = &io; + msg.msg_iovlen = 1; + msg.msg_control = buf; + msg.msg_controllen = sizeof(buf); + + cmsg = CMSG_FIRSTHDR(&msg); + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = SCM_RIGHTS; + cmsg->cmsg_len = CMSG_LEN(n * sizeof(int)); + + memcpy(CMSG_DATA(cmsg), fds, n * sizeof(int)); + + return sendmsg(socket, &msg, 0); +} + +static void print_help_and_exit(const char *prog, int exitcode) +{ + fprintf(stderr, "%s - load eBPF RSS program for qemu and pass eBPF fds" + " through unix socket.\n", prog); + fprintf(stderr, "\t--fd <num>, -f <num> - unix socket file descriptor" + " used to pass eBPF fds.\n"); + fprintf(stderr, "\t--help, -h - this help.\n"); + exit(exitcode); +} + +int main(int argc, char **argv) +{ + char *fd_string = NULL; + int unix_fd = 0; + struct EBPFRSSContext ctx = {}; + int fds[EBPF_RSS_MAX_FDS] = {}; + int ret = -1; + + for (;;) { + int c; + static struct option long_options[] = { + {"help", no_argument, 0, 'h'}, + {"fd", required_argument, 0, 'f'}, + {0, 0, 0, 0} + }; + c = getopt_long(argc, argv, "hf:", + long_options, NULL); + + if (c == -1) { + break; + } + + switch (c) { + case 'f': + fd_string = optarg; + break; + case 'h': + default: + print_help_and_exit(argv[0], + c == 'h' ? EXIT_SUCCESS : EXIT_FAILURE); + } + } + + if (!fd_string) { + fprintf(stderr, "Unix file descriptor not present.\n"); + print_help_and_exit(argv[0], EXIT_FAILURE); + } + + fprintf(stderr, "FD %s\n", fd_string); + + unix_fd = atoi(fd_string); + + if (!unix_fd) { + fprintf(stderr, "Unix file descriptor is invalid.\n"); + return EXIT_FAILURE; + } + + ebpf_rss_init(&ctx); + if (!ebpf_rss_load(&ctx)) { + fprintf(stderr, "Can't load ebpf.\n"); + return EXIT_FAILURE; + } + fds[0] = ctx.program_fd; + fds[1] = ctx.map_configuration; + fds[2] = ctx.map_toeplitz_key; + fds[3] = ctx.map_indirections_table; + + ret = send_fds(unix_fd, fds, EBPF_RSS_MAX_FDS); + if (ret < 0) { + fprintf(stderr, "Issue while sending fds: %s.\n", strerror(errno)); + } + + ebpf_rss_unload(&ctx); + + return ret < 0 ? EXIT_FAILURE : EXIT_SUCCESS; +} + diff --git a/meson.build b/meson.build index 626cf932c1..ce26bddead 100644 --- a/meson.build +++ b/meson.build @@ -2413,6 +2413,14 @@ if have_tools dependencies: [authz, crypto, io, qom, qemuutil, libcap_ng, mpathpersist], install: true) + + if libbpf.found() + executable('qemu-ebpf-rss-helper', files( + 'ebpf/qemu-ebpf-rss-helper.c', 'ebpf/ebpf_rss.c'), + dependencies: [qemuutil, libbpf, glib], + install: true, + install_dir: get_option('libexecdir')) + endif endif if 'CONFIG_IVSHMEM' in config_host -- 2.31.1
