examples/l3fwd/lpm_route_parse.c

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2022 Intel Corporation
 */

#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#include <sys/socket.h>

#include "l3fwd.h"
#include "l3fwd_route.h"

enum {
    CB_FLD_DST_ADDR,
    CB_FLD_IF_OUT,
    CB_FLD_MAX
};

struct lpm_route_rule *route_base_v4;
struct lpm_route_rule *route_base_v6;
int route_num_v4;
int route_num_v6;

/* Bypass comment and empty lines */
int
is_bypass_line(const char *buff)
{
    int i = 0;

    /* comment line */
    if (buff[0] == COMMENT_LEAD_CHAR)
        return 1;
    /* empty line */
    while (buff[i] != '\0') {
        if (!isspace(buff[i]))
            return 0;
        i++;
    }
    return 1;
}

static int
parse_ipv6_addr_mask(char *token, struct rte_ipv6_addr *ipv6, uint8_t *mask)
{
    char *sa, *sm, *sv;
    const char *dlm =  "/";

    sv = NULL;
    sa = strtok_r(token, dlm, &sv);
    if (sa == NULL)
        return -EINVAL;
    sm = strtok_r(NULL, dlm, &sv);
    if (sm == NULL)
        return -EINVAL;

    if (inet_pton(AF_INET6, sa, ipv6) != 1)
        return -EINVAL;

    GET_CB_FIELD(sm, *mask, 0, 128, 0);
    return 0;
}

static int
parse_ipv4_addr_mask(char *token, uint32_t *ipv4, uint8_t *mask)
{
    char *sa, *sm, *sv;
    const char *dlm =  "/";

    sv = NULL;
    sa = strtok_r(token, dlm, &sv);
    if (sa == NULL)
        return -EINVAL;
    sm = strtok_r(NULL, dlm, &sv);
    if (sm == NULL)
        return -EINVAL;

    if (inet_pton(AF_INET, sa, ipv4) != 1)
        return -EINVAL;

    GET_CB_FIELD(sm, *mask, 0, 32, 0);
    *ipv4 = ntohl(*ipv4);
    return 0;
}

static int
lpm_parse_v6_net(char *in, struct rte_ipv6_addr *v, uint8_t *mask_len)
{
    int32_t rc;

    /* get address. */
    rc = parse_ipv6_addr_mask(in, v, mask_len);

    return rc;
}

static int
lpm_parse_v6_rule(char *str, struct lpm_route_rule *v)
{
    int i, rc;
    char *s, *sp, *in[CB_FLD_MAX];
    static const char *dlm = " \t\n";
    int dim = CB_FLD_MAX;
    s = str;

    for (i = 0; i != dim; i++, s = NULL) {
        in[i] = strtok_r(s, dlm, &sp);
        if (in[i] == NULL)
            return -EINVAL;
    }

    rc = lpm_parse_v6_net(in[CB_FLD_DST_ADDR], &v->ip6, &v->depth);

    GET_CB_FIELD(in[CB_FLD_IF_OUT], v->if_out, 0, UINT8_MAX, 0);

    return rc;
}

static int
lpm_parse_v4_rule(char *str, struct lpm_route_rule *v)
{
    int i, rc;
    char *s, *sp, *in[CB_FLD_MAX];
    static const char *dlm = " \t\n";
    int dim = CB_FLD_MAX;
    s = str;

    for (i = 0; i != dim; i++, s = NULL) {
        in[i] = strtok_r(s, dlm, &sp);
        if (in[i] == NULL)
            return -EINVAL;
    }

    rc = parse_ipv4_addr_mask(in[CB_FLD_DST_ADDR], &v->ip, &v->depth);

    GET_CB_FIELD(in[CB_FLD_IF_OUT], v->if_out, 0, UINT8_MAX, 0);

    return rc;
}

static int
lpm_add_default_v4_rules(void)
{
    /* populate the LPM IPv4 table */
    unsigned int i, rule_size = sizeof(*route_base_v4);
    route_num_v4 = RTE_DIM(ipv4_l3fwd_route_array);

    route_base_v4 = calloc(route_num_v4, rule_size);

    for (i = 0; i < (unsigned int)route_num_v4; i++) {
        route_base_v4[i].ip = ipv4_l3fwd_route_array[i].ip;
        route_base_v4[i].depth = ipv4_l3fwd_route_array[i].depth;
        route_base_v4[i].if_out = ipv4_l3fwd_route_array[i].if_out;
    }
    return 0;
}

static int
lpm_add_default_v6_rules(void)
{
    /* populate the LPM IPv6 table */
    unsigned int i, rule_size = sizeof(*route_base_v6);
    route_num_v6 = RTE_DIM(ipv6_l3fwd_route_array);

    route_base_v6 = calloc(route_num_v6, rule_size);

    for (i = 0; i < (unsigned int)route_num_v6; i++) {
        route_base_v6[i].ip6 = ipv6_l3fwd_route_array[i].ip;
        route_base_v6[i].depth = ipv6_l3fwd_route_array[i].depth;
        route_base_v6[i].if_out = ipv6_l3fwd_route_array[i].if_out;
    }
    return 0;
}

static int
lpm_add_rules(const char *rule_path,
        struct lpm_route_rule **proute_base,
        int (*parser)(char *, struct lpm_route_rule *))
{
    struct lpm_route_rule *route_rules;
    struct lpm_route_rule *next;
    unsigned int route_num = 0;
    unsigned int route_cnt = 0;
    char buff[LINE_MAX];
    FILE *fh;
    unsigned int i = 0, rule_size = sizeof(*next);
    int val;

    *proute_base = NULL;
    fh = fopen(rule_path, "rb");
    if (fh == NULL)
        return -EINVAL;

    while ((fgets(buff, LINE_MAX, fh) != NULL)) {
        if (buff[0] == ROUTE_LEAD_CHAR)
            route_num++;
    }

    if (route_num == 0) {
        fclose(fh);
        return -EINVAL;
    }

    val = fseek(fh, 0, SEEK_SET);
    if (val < 0) {
        fclose(fh);
        return -EINVAL;
    }

    route_rules = calloc(route_num, rule_size);

    if (route_rules == NULL) {
        fclose(fh);
        return -EINVAL;
    }

    i = 0;
    while (fgets(buff, LINE_MAX, fh) != NULL) {
        i++;
        if (is_bypass_line(buff))
            continue;

        char s = buff[0];

        /* Route entry */
        if (s == ROUTE_LEAD_CHAR)
            next = &route_rules[route_cnt];

        /* Illegal line */
        else {
            RTE_LOG(ERR, L3FWD,
                "%s Line %u: should start with leading "
                "char %c\n",
                rule_path, i, ROUTE_LEAD_CHAR);
            fclose(fh);
            free(route_rules);
            return -EINVAL;
        }

        if (parser(buff + 1, next) != 0) {
            RTE_LOG(ERR, L3FWD,
                "%s Line %u: parse rules error\n",
                rule_path, i);
            fclose(fh);
            free(route_rules);
            return -EINVAL;
        }

        route_cnt++;
    }

    fclose(fh);

    *proute_base = route_rules;

    return route_cnt;
}

void
lpm_free_routes(void)
{
    free(route_base_v4);
    free(route_base_v6);
    route_base_v4 = NULL;
    route_base_v6 = NULL;
    route_num_v4 = 0;
    route_num_v6 = 0;
}

/* Load rules from the input file */
void
read_config_files_lpm(void)
{
    if (parm_config.rule_ipv4_name != NULL &&
            parm_config.rule_ipv6_name != NULL) {
        /* ipv4 check */
        route_num_v4 = lpm_add_rules(parm_config.rule_ipv4_name,
                    &route_base_v4, &lpm_parse_v4_rule);
        if (route_num_v4 < 0) {
            lpm_free_routes();
            rte_exit(EXIT_FAILURE, "Failed to add IPv4 rules\n");
        }

        /* ipv6 check */
        route_num_v6 = lpm_add_rules(parm_config.rule_ipv6_name,
                    &route_base_v6, &lpm_parse_v6_rule);
        if (route_num_v6 < 0) {
            lpm_free_routes();
            rte_exit(EXIT_FAILURE, "Failed to add IPv6 rules\n");
        }
    } else {
        RTE_LOG(INFO, L3FWD, "Missing 1 or more rule files, using default instead\n");
        if (lpm_add_default_v4_rules() < 0) {
            lpm_free_routes();
            rte_exit(EXIT_FAILURE, "Failed to add default IPv4 rules\n");
        }
        if (lpm_add_default_v6_rules() < 0) {
            lpm_free_routes();
            rte_exit(EXIT_FAILURE, "Failed to add default IPv6 rules\n");
        }
    }
}