lib/librte_bpf/bpf_load.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2018 Intel Corporation
   3  */
   4
   5 #include <stdarg.h>
   6 #include <stdio.h>
   7 #include <string.h>
   8 #include <errno.h>
   9 #include <stdint.h>
  10 #include <unistd.h>
  11 #include <inttypes.h>
  12
  13 #include <rte_common.h>
  14 #include <rte_log.h>
  15 #include <rte_debug.h>
  16 #include <rte_memory.h>
  17 #include <rte_eal.h>
  18 #include <rte_byteorder.h>
  19 #include <rte_errno.h>
  20
  21 #include "bpf_impl.h"
  22
  23 static struct rte_bpf *
  24 bpf_load(const struct rte_bpf_prm *prm)
  25 {
  26         uint8_t *buf;
  27         struct rte_bpf *bpf;
  28         size_t sz, bsz, insz, xsz;
  29
  30         xsz =  prm->nb_xsym * sizeof(prm->xsym[0]);
  31         insz = prm->nb_ins * sizeof(prm->ins[0]);
  32         bsz = sizeof(bpf[0]);
  33         sz = insz + xsz + bsz;
  34
  35         buf = mmap(NULL, sz, PROT_READ | PROT_WRITE,
  36                 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  37         if (buf == MAP_FAILED)
  38                 return NULL;
  39
  40         bpf = (void *)buf;
  41         bpf->sz = sz;
  42
  43         memcpy(&bpf->prm, prm, sizeof(bpf->prm));
  44
  45         memcpy(buf + bsz, prm->xsym, xsz);
  46         memcpy(buf + bsz + xsz, prm->ins, insz);
  47
  48         bpf->prm.xsym = (void *)(buf + bsz);
  49         bpf->prm.ins = (void *)(buf + bsz + xsz);
  50
  51         return bpf;
  52 }
  53
  54 /*
  55  * Check that user provided external symbol.
  56  */
  57 static int
  58 bpf_check_xsym(const struct rte_bpf_xsym *xsym)
  59 {
  60         uint32_t i;
  61
  62         if (xsym->name == NULL)
  63                 return -EINVAL;
  64
  65         if (xsym->type == RTE_BPF_XTYPE_VAR) {
  66                 if (xsym->var.desc.type == RTE_BPF_ARG_UNDEF)
  67                         return -EINVAL;
  68         } else if (xsym->type == RTE_BPF_XTYPE_FUNC) {
  69
  70                 if (xsym->func.nb_args > EBPF_FUNC_MAX_ARGS)
  71                         return -EINVAL;
  72
  73                 /* check function arguments */
  74                 for (i = 0; i != xsym->func.nb_args; i++) {
  75                         if (xsym->func.args[i].type == RTE_BPF_ARG_UNDEF)
  76                                 return -EINVAL;
  77                 }
  78
  79                 /* check return value info */
  80                 if (xsym->func.ret.type != RTE_BPF_ARG_UNDEF &&
  81                                 xsym->func.ret.size == 0)
  82                         return -EINVAL;
  83         } else
  84                 return -EINVAL;
  85
  86         return 0;
  87 }
  88
  89 struct rte_bpf *
  90 rte_bpf_load(const struct rte_bpf_prm *prm)
  91 {
  92         struct rte_bpf *bpf;
  93         int32_t rc;
  94         uint32_t i;
  95
  96         if (prm == NULL || prm->ins == NULL ||
  97                         (prm->nb_xsym != 0 && prm->xsym == NULL)) {
  98                 rte_errno = EINVAL;
  99                 return NULL;
 100         }
 101
 102         rc = 0;
 103         for (i = 0; i != prm->nb_xsym && rc == 0; i++)
 104                 rc = bpf_check_xsym(prm->xsym + i);
 105
 106         if (rc != 0) {
 107                 rte_errno = -rc;
 108                 RTE_BPF_LOG(ERR, "%s: %d-th xsym is invalid\n", __func__, i);
 109                 return NULL;
 110         }
 111
 112         bpf = bpf_load(prm);
 113         if (bpf == NULL) {
 114                 rte_errno = ENOMEM;
 115                 return NULL;
 116         }
 117
 118         rc = bpf_validate(bpf);
 119         if (rc == 0) {
 120                 bpf_jit(bpf);
 121                 if (mprotect(bpf, bpf->sz, PROT_READ) != 0)
 122                         rc = -ENOMEM;
 123         }
 124
 125         if (rc != 0) {
 126                 rte_bpf_destroy(bpf);
 127                 rte_errno = -rc;
 128                 return NULL;
 129         }
 130
 131         return bpf;
 132 }
 133
 134 #ifndef RTE_LIBRTE_BPF_ELF
 135 struct rte_bpf *
 136 rte_bpf_elf_load(const struct rte_bpf_prm *prm, const char *fname,
 137         const char *sname)
 138 {
 139         if (prm == NULL || fname == NULL || sname == NULL) {
 140                 rte_errno = EINVAL;
 141                 return NULL;
 142         }
 143
 144         RTE_BPF_LOG(ERR, "%s() is not supported with current config\n"
 145                 "rebuild with libelf installed\n",
 146                 __func__);
 147         rte_errno = ENOTSUP;
 148         return NULL;
 149 }
 150 #endif