246 lines
7.6 KiB
C
246 lines
7.6 KiB
C
#define _GNU_SOURCE
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#include <sched.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <arpa/inet.h>
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#include <linux/rtnetlink.h>
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#include <sys/socket.h>
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// 定义一个足够大的缓冲区来接收Netlink消息
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#define NL_BUFSIZE 8192
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// 结构体，用于将请求消息封装起来
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struct nl_req_t {
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struct nlmsghdr nlh;
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struct ifaddrmsg ifa;
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};
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void parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len) {
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memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
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while (RTA_OK(rta, len)) {
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if (rta->rta_type <= max) {
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tb[rta->rta_type] = rta;
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}
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rta = RTA_NEXT(rta, len);
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}
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}
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int run_netlink_test() {
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int sock_fd;
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struct sockaddr_nl sa_nl;
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struct nl_req_t req;
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// struct iovec iov;
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// struct msghdr msg;
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// struct sockaddr_nl src_addr; // 用于接收发送方的地址
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char buf[NL_BUFSIZE];
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ssize_t len;
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struct nlmsghdr *nlh;
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// 创建Netlink套接字
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sock_fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
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if (sock_fd < 0) {
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perror("socket creation failed");
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return EXIT_FAILURE;
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}
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// 设置Netlink地址
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memset(&sa_nl, 0, sizeof(sa_nl));
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sa_nl.nl_family = AF_NETLINK;
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sa_nl.nl_pid = getpid(); // 使用进程ID作为地址
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// 绑定Netlink套接字
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if (bind(sock_fd, (struct sockaddr *)&sa_nl, sizeof(sa_nl)) < 0) {
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perror("socket bind failed");
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close(sock_fd);
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return EXIT_FAILURE;
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}
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// 构建RTM_GETADDR请求消息
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memset(&req, 0, sizeof(req));
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req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
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// 这是关键：设置DUMP标志以获取所有地址
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req.nlh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
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req.nlh.nlmsg_type = RTM_GETADDR;
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req.nlh.nlmsg_seq = 1; // 序列号，用于匹配请求和响应
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req.nlh.nlmsg_pid = getpid();
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req.ifa.ifa_family =
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AF_INET; // 只请求 IPv4 地址 (也可以用 AF_UNSPEC 获取所有)
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// 内核的目标地址
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struct sockaddr_nl dest_addr;
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memset(&dest_addr, 0, sizeof(dest_addr));
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dest_addr.nl_family = AF_NETLINK;
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dest_addr.nl_pid = 0; // 0 for the kernel
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dest_addr.nl_groups = 0; // Unicast
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// 发送请求到内核
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if (sendto(sock_fd,
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&req,
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req.nlh.nlmsg_len,
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0,
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(struct sockaddr *)&dest_addr,
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sizeof(dest_addr)) < 0) {
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perror("send failed");
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close(sock_fd);
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return EXIT_FAILURE;
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}
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printf("Sent RTM_GETADDR request with DUMP flag.\n\n");
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// // 准备 recvmsg 所需的结构体
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// // iovec 指向我们的主数据缓冲区
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// iov.iov_base = buf;
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// iov.iov_len = sizeof(buf);
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// // msghdr 将所有部分组合在一起
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// msg.msg_name = &src_addr; // 填充发送方地址
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// msg.msg_namelen = sizeof(src_addr);
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// msg.msg_iov = &iov; // 指向数据缓冲区
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// msg.msg_iovlen = 1;
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// msg.msg_control = NULL; // 我们暂时不处理控制消息
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// msg.msg_controllen = 0;
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int received_messages = 0;
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// 循环接收响应
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while ((len = recv(sock_fd, buf, sizeof(buf), 0)) > 0) {
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// ssize_t len = recvmsg(sock_fd, &msg, 0);
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// if (len < 0) {
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// perror("recvmsg failed");
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// break;
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// }
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// if (len == 0) {
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// printf("EOF on netlink socket\n");
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// break;
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// }
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// if (msg.msg_flags & MSG_TRUNC) {
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// fprintf(
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// stderr,
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// "Warning: Message was truncated. Buffer may be too small.\n");
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// }
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// 使用 NLMSG_OK 遍历缓冲区中可能存在的多条消息
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for (nlh = (struct nlmsghdr *)buf; NLMSG_OK(nlh, len);
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nlh = NLMSG_NEXT(nlh, len)) {
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// 如果是 DUMP 结束的标志，则退出循环
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if (nlh->nlmsg_type == NLMSG_DONE) {
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printf("--- End of DUMP ---\n");
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if (!received_messages) {
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printf("(Received an empty list as expected)\n");
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}
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close(sock_fd);
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return EXIT_SUCCESS;
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}
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// 如果是错误消息
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if (nlh->nlmsg_type == NLMSG_ERROR) {
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struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(nlh);
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fprintf(stderr,
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"Netlink error received: %s\n",
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strerror(-err->error));
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close(sock_fd);
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return EXIT_FAILURE;
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}
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// 只处理我们期望的 RTM_NEWADDR 消息
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if (nlh->nlmsg_type != RTM_NEWADDR) {
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printf("Received unexpected message type: %d\n",
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nlh->nlmsg_type);
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continue;
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}
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// printf("Received message from PID: %u\n", src_addr.nl_pid);
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// 表明我们至少接收到了一条信息
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received_messages = 1;
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struct ifaddrmsg *ifa = (struct ifaddrmsg *)NLMSG_DATA(nlh);
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struct rtattr *rta_tb[IFA_MAX + 1];
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// 解析消息中的路由属性
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int rta_len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifa));
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parse_rtattr(rta_tb, IFA_MAX, IFA_RTA(ifa), rta_len);
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printf("Interface Index: %d, PrefixLen: %d, Scope: %d\n",
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ifa->ifa_index,
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ifa->ifa_prefixlen,
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ifa->ifa_scope);
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char ip_addr_str[INET6_ADDRSTRLEN];
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// 打印 IFA_LABEL (对应你的 AddrAttr::Label)
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if (rta_tb[IFA_LABEL]) {
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printf("\tLabel: %s\n", (char *)RTA_DATA(rta_tb[IFA_LABEL]));
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}
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// 打印 IFA_ADDRESS (对应你的 AddrAttr::Address)
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if (rta_tb[IFA_ADDRESS]) {
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inet_ntop(ifa->ifa_family,
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RTA_DATA(rta_tb[IFA_ADDRESS]),
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ip_addr_str,
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sizeof(ip_addr_str));
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printf("\tAddress: %s\n", ip_addr_str);
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}
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// 打印 IFA_LOCAL (对应你的 AddrAttr::Local)
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if (rta_tb[IFA_LOCAL]) {
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inet_ntop(ifa->ifa_family,
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RTA_DATA(rta_tb[IFA_LOCAL]),
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ip_addr_str,
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sizeof(ip_addr_str));
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printf("\tLocal: %s\n", ip_addr_str);
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}
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printf("----------------------------------------\n");
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}
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}
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if (len < 0) {
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perror("recv failed");
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}
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close(sock_fd);
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return EXIT_SUCCESS;
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}
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int main(int argc, char *argv[]) {
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printf("=========== STAGE 1: Testing in Default Network Namespace "
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"===========\n");
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if (run_netlink_test() != 0) {
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fprintf(stderr, "Test failed in the default namespace.\n");
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return EXIT_FAILURE;
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}
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printf("\n\n=========== STAGE 2: Creating and Testing in a New Network "
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"Namespace ===========\n");
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// ** 关键步骤：创建新的网络命名空间 **
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// 这个调用会将当前进程移入一个新的、隔离的网络栈中
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if (unshare(CLONE_NEWNET) == -1) {
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perror("unshare(CLONE_NEWNET) failed");
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fprintf(stderr,
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"This test requires root privileges (e.g., 'sudo "
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"./your_program').\n");
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return EXIT_FAILURE;
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}
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printf("Successfully created and entered a new network namespace.\n");
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// 在新的命名空间中再次运行同样的测试
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if (run_netlink_test() != 0) {
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fprintf(stderr, "Test failed in the new namespace.\n");
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return EXIT_FAILURE;
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}
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printf("\nAll tests completed successfully.\n");
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return EXIT_SUCCESS;
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} |