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/* SPDX-License-Identifier: BSD-3-Clause
* Copyright 2017 Mellanox Technologies, Ltd
*/
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/queue.h>
#include <rte_malloc.h>
#include <rte_eth_tap.h>
#include <tap_flow.h>
#include <tap_autoconf.h>
#include <tap_tcmsgs.h>
#include <tap_bpf.h>
#include <tap_bpf_insns.h>
/**
* Load BPF program (section cls_q) into the kernel and return a bpf fd
*
* @param queue_idx
* Queue index matching packet cb
*
* @return
* -1 if the BPF program couldn't be loaded. An fd (int) otherwise.
*/
int tap_flow_bpf_cls_q(__u32 queue_idx)
{
cls_q_insns[1].imm = queue_idx;
return bpf_load(BPF_PROG_TYPE_SCHED_CLS,
(struct bpf_insn *)cls_q_insns,
RTE_DIM(cls_q_insns),
"Dual BSD/GPL");
}
/**
* Load BPF program (section l3_l4) into the kernel and return a bpf fd.
*
* @param[in] key_idx
* RSS MAP key index
*
* @param[in] map_fd
* BPF RSS map file descriptor
*
* @return
* -1 if the BPF program couldn't be loaded. An fd (int) otherwise.
*/
int tap_flow_bpf_calc_l3_l4_hash(__u32 key_idx, int map_fd)
{
l3_l4_hash_insns[4].imm = key_idx;
l3_l4_hash_insns[9].imm = map_fd;
return bpf_load(BPF_PROG_TYPE_SCHED_ACT,
(struct bpf_insn *)l3_l4_hash_insns,
RTE_DIM(l3_l4_hash_insns),
"Dual BSD/GPL");
}
/**
* Helper function to convert a pointer to unsigned 64 bits
*
* @param[in] ptr
* pointer to address
*
* @return
* 64 bit unsigned long type of pointer address
*/
static inline __u64 ptr_to_u64(const void *ptr)
{
return (__u64)(unsigned long)ptr;
}
/**
* Call BPF system call
*
* @param[in] cmd
* BPF command for program loading, map creation, map entry update, etc
*
* @param[in] attr
* System call attributes relevant to system call command
*
* @param[in] size
* size of attr parameter
*
* @return
* -1 if BPF system call failed, 0 otherwise
*/
static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
unsigned int size)
{
return syscall(__NR_bpf, cmd, attr, size);
}
/**
* Load BPF instructions to kernel
*
* @param[in] type
* BPF program type: classifieir or action
*
* @param[in] insns
* Array of BPF instructions (equivalent to BPF instructions)
*
* @param[in] insns_cnt
* Number of BPF instructions (size of array)
*
* @param[in] lincense
* License string that must be acknowledged by the kernel
*
* @return
* -1 if the BPF program couldn't be loaded, fd (file descriptor) otherwise
*/
static int bpf_load(enum bpf_prog_type type,
const struct bpf_insn *insns,
size_t insns_cnt,
const char *license)
{
union bpf_attr attr = {};
bzero(&attr, sizeof(attr));
attr.prog_type = type;
attr.insn_cnt = (__u32)insns_cnt;
attr.insns = ptr_to_u64(insns);
attr.license = ptr_to_u64(license);
attr.log_buf = ptr_to_u64(NULL);
attr.log_level = 0;
attr.kern_version = 0;
return sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
}
/**
* Create BPF map for RSS rules
*
* @param[in] key_size
* map RSS key size
*
* @param[in] value_size
* Map RSS value size
*
* @param[in] max_entries
* Map max number of RSS entries (limit on max RSS rules)
*
* @return
* -1 if BPF map couldn't be created, map fd otherwise
*/
int tap_flow_bpf_rss_map_create(unsigned int key_size,
unsigned int value_size,
unsigned int max_entries)
{
union bpf_attr attr = {};
bzero(&attr, sizeof(attr));
attr.map_type = BPF_MAP_TYPE_HASH;
attr.key_size = key_size;
attr.value_size = value_size;
attr.max_entries = max_entries;
return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
}
/**
* Update RSS entry in BPF map
*
* @param[in] fd
* RSS map fd
*
* @param[in] key
* Pointer to RSS key whose entry is updated
*
* @param[in] value
* Pointer to RSS new updated value
*
* @return
* -1 if RSS entry failed to be updated, 0 otherwise
*/
int tap_flow_bpf_update_rss_elem(int fd, void *key, void *value)
{
union bpf_attr attr = {};
bzero(&attr, sizeof(attr));
attr.map_type = BPF_MAP_TYPE_HASH;
attr.map_fd = fd;
attr.key = ptr_to_u64(key);
attr.value = ptr_to_u64(value);
attr.flags = BPF_ANY;
return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
}
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