生成一段radius协议解析代码，参数为radius负载payload，以及负载长度radiusLen

以下是使用 C 语言生成一段简单的 RADIUS 协议解析代码，参数为 radius 负载 payload 和负载长度 radiusLen：

#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>

#define RADIUS_CODE_LEN 1
#define RADIUS_ID_LEN 1
#define RADIUS_LENGTH_LEN 2
#define RADIUS_AUTH_LEN 16
#define RADIUS_ATTR_TYPE_LEN 1
#define RADIUS_ATTR_LEN_LEN 1
#define RADIUS_ATTR_VALUE_LEN 253

typedef struct {
    uint8_t code;
    uint8_t id;
    uint16_t length;
    uint8_t auth[RADIUS_AUTH_LEN];
    uint8_t attrs[];
} radius_packet;

typedef struct {
    uint8_t type;
    uint8_t length;
    uint8_t value[RADIUS_ATTR_VALUE_LEN];
} radius_attribute;

void radius_parse(uint8_t *payload, size_t radiusLen) {
    radius_packet *packet = (radius_packet *) payload;

    // 解析固定头部字段
    uint8_t code = packet->code;
    uint8_t id = packet->id;
    uint16_t length = ntohs(packet->length);
    uint8_t *auth = packet->auth;

    printf("Code: %u\n", code);
    printf("ID: %u\n", id);
    printf("Length: %u\n", length);

    // 解析可变长度的属性字段
    uint8_t *attr_ptr = packet->attrs;
    size_t attr_len = length - RADIUS_CODE_LEN - RADIUS_ID_LEN - RADIUS_LENGTH_LEN - RADIUS_AUTH_LEN;
    while (attr_len > 0) {
        radius_attribute *attr = (radius_attribute *) attr_ptr;
        uint8_t type = attr->type;
        uint8_t attr_length = attr->length;
        uint8_t *value = attr->value;

        printf("Attribute Type: %u\n", type);
        printf("Attribute Length: %u\n", attr_length);
        printf("Attribute Value: %.*s\n", attr_length, value);

        attr_len -= (RADIUS_ATTR_TYPE_LEN + RADIUS_ATTR_LEN_LEN + attr_length);
        attr_ptr += (RADIUS_ATTR_TYPE_LEN + RADIUS_ATTR_LEN_LEN + attr_length);
    }
}

int main() {
    uint8_t payload[] = {0x01, 0x02, 0x00, 0x2a, 0x2d, 0x68, 0x4e, 0x41, 0x35, 0x7f, 0x2e, 0x6a, 0x3c, 0x75, 0x29, 0x62, 0x6b, 0x77, 0x0e, 0x06, 0x00, 0x1b, 0x7d, 0x51, 0x35, 0x2d, 0x38, 0x2d, 0x31, 0x33, 0x2d, 0x35, 0x34, 0x2d, 0x41, 0x55, 0x54, 0x48, 0x0f, 0x06, 0x00, 0x1c, 0x00, 0x00, 0x00, 0x00};
    size_t radiusLen = sizeof(payload);
    radius_parse(payload, radiusLen);
    return 0;
}

这段代码使用了 C 语言的结构体来表示 RADIUS 协议的包结构和属性结构，并使用了网络字节序转换函数 ntohs() 来将网络字节序转换为主机字节序。在主函数中，我们可以通过传入参数 payload 和 radiusLen 来解析 RADIUS 协议的包内容。