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Diffstat (limited to '')
| -rw-r--r-- | tc/e_bpf.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/tc/e_bpf.c b/tc/e_bpf.c new file mode 100644 index 0000000..517ee5b --- /dev/null +++ b/tc/e_bpf.c @@ -0,0 +1,180 @@ +/* + * e_bpf.c BPF exec proxy + * + * This program is free software; you can distribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Authors: Daniel Borkmann <daniel@iogearbox.net> + */ + +#include <stdio.h> +#include <unistd.h> + +#include "utils.h" + +#include "tc_util.h" + +#include "bpf_util.h" +#include "bpf_elf.h" +#include "bpf_scm.h" + +#define BPF_DEFAULT_CMD "/bin/sh" + +static char *argv_default[] = { BPF_DEFAULT_CMD, NULL }; + +static void explain(void) +{ + fprintf(stderr, + "Usage: ... bpf [ import UDS_FILE ] [ run CMD ]\n" + " ... bpf [ debug ]\n" + " ... bpf [ graft MAP_FILE ] [ key KEY ]\n" + " `... [ object-file OBJ_FILE ] [ type TYPE ] [ section NAME ] [ verbose ]\n" + " `... [ object-pinned PROG_FILE ]\n" + "\n" + "Where UDS_FILE provides the name of a unix domain socket file\n" + "to import eBPF maps and the optional CMD denotes the command\n" + "to be executed (default: \'%s\').\n" + "Where MAP_FILE points to a pinned map, OBJ_FILE to an object file\n" + "and PROG_FILE to a pinned program. TYPE can be {cls, act}, where\n" + "\'cls\' is default. KEY is optional and can be inferred from the\n" + "section name, otherwise it needs to be provided.\n", + BPF_DEFAULT_CMD); +} + +static int bpf_num_env_entries(void) +{ + char **envp; + int num; + + for (num = 0, envp = environ; *envp != NULL; envp++) + num++; + return num; +} + +static int parse_bpf(struct exec_util *eu, int argc, char **argv) +{ + char **argv_run = argv_default, **envp_run, *tmp; + int ret, i, env_old, env_num, env_map; + const char *bpf_uds_name = NULL; + int fds[BPF_SCM_MAX_FDS] = {}; + struct bpf_map_aux aux = {}; + + if (argc == 0) + return 0; + + while (argc > 0) { + if (matches(*argv, "run") == 0) { + NEXT_ARG(); + argv_run = argv; + break; + } else if (matches(*argv, "import") == 0) { + NEXT_ARG(); + bpf_uds_name = *argv; + } else if (matches(*argv, "debug") == 0 || + matches(*argv, "dbg") == 0) { + if (bpf_trace_pipe()) + fprintf(stderr, + "No trace pipe, tracefs not mounted?\n"); + return -1; + } else if (matches(*argv, "graft") == 0) { + const char *bpf_map_path; + bool has_key = false; + uint32_t key; + + NEXT_ARG(); + bpf_map_path = *argv; + NEXT_ARG(); + if (matches(*argv, "key") == 0) { + NEXT_ARG(); + if (get_unsigned(&key, *argv, 0)) { + fprintf(stderr, "Illegal \"key\"\n"); + return -1; + } + has_key = true; + NEXT_ARG(); + } + return bpf_graft_map(bpf_map_path, has_key ? + &key : NULL, argc, argv); + } else { + explain(); + return -1; + } + + NEXT_ARG_FWD(); + } + + if (!bpf_uds_name) { + fprintf(stderr, "bpf: No import parameter provided!\n"); + explain(); + return -1; + } + + if (argv_run != argv_default && argc == 0) { + fprintf(stderr, "bpf: No run command provided!\n"); + explain(); + return -1; + } + + ret = bpf_recv_map_fds(bpf_uds_name, fds, &aux, ARRAY_SIZE(fds)); + if (ret < 0) { + fprintf(stderr, "bpf: Could not receive fds!\n"); + return -1; + } + + if (aux.num_ent == 0) { + envp_run = environ; + goto out; + } + + env_old = bpf_num_env_entries(); + env_num = env_old + aux.num_ent + 2; + env_map = env_old + 1; + + envp_run = malloc(sizeof(*envp_run) * env_num); + if (!envp_run) { + fprintf(stderr, "bpf: No memory left to allocate env!\n"); + goto err; + } + + for (i = 0; i < env_old; i++) + envp_run[i] = environ[i]; + + ret = asprintf(&tmp, "BPF_NUM_MAPS=%u", aux.num_ent); + if (ret < 0) + goto err_free; + + envp_run[env_old] = tmp; + + for (i = env_map; i < env_num - 1; i++) { + ret = asprintf(&tmp, "BPF_MAP%u=%u", + aux.ent[i - env_map].id, + fds[i - env_map]); + if (ret < 0) + goto err_free_env; + + envp_run[i] = tmp; + } + + envp_run[env_num - 1] = NULL; +out: + ret = execvpe(argv_run[0], argv_run, envp_run); + free(envp_run); + return ret; + +err_free_env: + for (--i; i >= env_old; i--) + free(envp_run[i]); +err_free: + free(envp_run); +err: + for (i = 0; i < aux.num_ent; i++) + close(fds[i]); + return -1; +} + +struct exec_util bpf_exec_util = { + .id = "bpf", + .parse_eopt = parse_bpf, +}; |