1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 2cf9b1199SSargun Dhillon #include <stdio.h> 3cf9b1199SSargun Dhillon #include <assert.h> 4cf9b1199SSargun Dhillon #include <unistd.h> 52bf3e2efSJakub Kicinski #include <bpf/bpf.h> 63677d0a1SDaniel T. Lee #include <bpf/libbpf.h> 7cf9b1199SSargun Dhillon #include <sys/socket.h> 8cf9b1199SSargun Dhillon #include <netinet/in.h> 9cf9b1199SSargun Dhillon #include <arpa/inet.h> 10cf9b1199SSargun Dhillon 11cf9b1199SSargun Dhillon int main(int ac, char **argv) 12cf9b1199SSargun Dhillon { 13cf9b1199SSargun Dhillon struct sockaddr_in *serv_addr_in, *mapped_addr_in, *tmp_addr_in; 143677d0a1SDaniel T. Lee struct sockaddr serv_addr, mapped_addr, tmp_addr; 153677d0a1SDaniel T. Lee int serverfd, serverconnfd, clientfd, map_fd; 163677d0a1SDaniel T. Lee struct bpf_link *link = NULL; 173677d0a1SDaniel T. Lee struct bpf_program *prog; 183677d0a1SDaniel T. Lee struct bpf_object *obj; 193677d0a1SDaniel T. Lee socklen_t sockaddr_len; 20cf9b1199SSargun Dhillon char filename[256]; 21cf9b1199SSargun Dhillon char *ip; 22cf9b1199SSargun Dhillon 23cf9b1199SSargun Dhillon serv_addr_in = (struct sockaddr_in *)&serv_addr; 24cf9b1199SSargun Dhillon mapped_addr_in = (struct sockaddr_in *)&mapped_addr; 25cf9b1199SSargun Dhillon tmp_addr_in = (struct sockaddr_in *)&tmp_addr; 26cf9b1199SSargun Dhillon 27cf9b1199SSargun Dhillon snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); 283677d0a1SDaniel T. Lee obj = bpf_object__open_file(filename, NULL); 293677d0a1SDaniel T. Lee if (libbpf_get_error(obj)) { 303677d0a1SDaniel T. Lee fprintf(stderr, "ERROR: opening BPF object file failed\n"); 313677d0a1SDaniel T. Lee return 0; 323677d0a1SDaniel T. Lee } 33cf9b1199SSargun Dhillon 343677d0a1SDaniel T. Lee prog = bpf_object__find_program_by_name(obj, "bpf_prog1"); 353677d0a1SDaniel T. Lee if (libbpf_get_error(prog)) { 363677d0a1SDaniel T. Lee fprintf(stderr, "ERROR: finding a prog in obj file failed\n"); 373677d0a1SDaniel T. Lee goto cleanup; 383677d0a1SDaniel T. Lee } 393677d0a1SDaniel T. Lee 403677d0a1SDaniel T. Lee /* load BPF program */ 413677d0a1SDaniel T. Lee if (bpf_object__load(obj)) { 423677d0a1SDaniel T. Lee fprintf(stderr, "ERROR: loading BPF object file failed\n"); 433677d0a1SDaniel T. Lee goto cleanup; 443677d0a1SDaniel T. Lee } 453677d0a1SDaniel T. Lee 463677d0a1SDaniel T. Lee map_fd = bpf_object__find_map_fd_by_name(obj, "dnat_map"); 473677d0a1SDaniel T. Lee if (map_fd < 0) { 483677d0a1SDaniel T. Lee fprintf(stderr, "ERROR: finding a map in obj file failed\n"); 493677d0a1SDaniel T. Lee goto cleanup; 503677d0a1SDaniel T. Lee } 513677d0a1SDaniel T. Lee 523677d0a1SDaniel T. Lee link = bpf_program__attach(prog); 533677d0a1SDaniel T. Lee if (libbpf_get_error(link)) { 543677d0a1SDaniel T. Lee fprintf(stderr, "ERROR: bpf_program__attach failed\n"); 553677d0a1SDaniel T. Lee link = NULL; 563677d0a1SDaniel T. Lee goto cleanup; 57cf9b1199SSargun Dhillon } 58cf9b1199SSargun Dhillon 59cf9b1199SSargun Dhillon assert((serverfd = socket(AF_INET, SOCK_STREAM, 0)) > 0); 60cf9b1199SSargun Dhillon assert((clientfd = socket(AF_INET, SOCK_STREAM, 0)) > 0); 61cf9b1199SSargun Dhillon 62cf9b1199SSargun Dhillon /* Bind server to ephemeral port on lo */ 63cf9b1199SSargun Dhillon memset(&serv_addr, 0, sizeof(serv_addr)); 64cf9b1199SSargun Dhillon serv_addr_in->sin_family = AF_INET; 65cf9b1199SSargun Dhillon serv_addr_in->sin_port = 0; 66cf9b1199SSargun Dhillon serv_addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK); 67cf9b1199SSargun Dhillon 68cf9b1199SSargun Dhillon assert(bind(serverfd, &serv_addr, sizeof(serv_addr)) == 0); 69cf9b1199SSargun Dhillon 70cf9b1199SSargun Dhillon sockaddr_len = sizeof(serv_addr); 71cf9b1199SSargun Dhillon assert(getsockname(serverfd, &serv_addr, &sockaddr_len) == 0); 72cf9b1199SSargun Dhillon ip = inet_ntoa(serv_addr_in->sin_addr); 73cf9b1199SSargun Dhillon printf("Server bound to: %s:%d\n", ip, ntohs(serv_addr_in->sin_port)); 74cf9b1199SSargun Dhillon 75cf9b1199SSargun Dhillon memset(&mapped_addr, 0, sizeof(mapped_addr)); 76cf9b1199SSargun Dhillon mapped_addr_in->sin_family = AF_INET; 77cf9b1199SSargun Dhillon mapped_addr_in->sin_port = htons(5555); 78cf9b1199SSargun Dhillon mapped_addr_in->sin_addr.s_addr = inet_addr("255.255.255.255"); 79cf9b1199SSargun Dhillon 803677d0a1SDaniel T. Lee assert(!bpf_map_update_elem(map_fd, &mapped_addr, &serv_addr, BPF_ANY)); 81cf9b1199SSargun Dhillon 82cf9b1199SSargun Dhillon assert(listen(serverfd, 5) == 0); 83cf9b1199SSargun Dhillon 84cf9b1199SSargun Dhillon ip = inet_ntoa(mapped_addr_in->sin_addr); 85cf9b1199SSargun Dhillon printf("Client connecting to: %s:%d\n", 86cf9b1199SSargun Dhillon ip, ntohs(mapped_addr_in->sin_port)); 87cf9b1199SSargun Dhillon assert(connect(clientfd, &mapped_addr, sizeof(mapped_addr)) == 0); 88cf9b1199SSargun Dhillon 89cf9b1199SSargun Dhillon sockaddr_len = sizeof(tmp_addr); 90cf9b1199SSargun Dhillon ip = inet_ntoa(tmp_addr_in->sin_addr); 91cf9b1199SSargun Dhillon assert((serverconnfd = accept(serverfd, &tmp_addr, &sockaddr_len)) > 0); 92cf9b1199SSargun Dhillon printf("Server received connection from: %s:%d\n", 93cf9b1199SSargun Dhillon ip, ntohs(tmp_addr_in->sin_port)); 94cf9b1199SSargun Dhillon 95cf9b1199SSargun Dhillon sockaddr_len = sizeof(tmp_addr); 96cf9b1199SSargun Dhillon assert(getpeername(clientfd, &tmp_addr, &sockaddr_len) == 0); 97cf9b1199SSargun Dhillon ip = inet_ntoa(tmp_addr_in->sin_addr); 98cf9b1199SSargun Dhillon printf("Client's peer address: %s:%d\n", 99cf9b1199SSargun Dhillon ip, ntohs(tmp_addr_in->sin_port)); 100cf9b1199SSargun Dhillon 101cf9b1199SSargun Dhillon /* Is the server's getsockname = the socket getpeername */ 102cf9b1199SSargun Dhillon assert(memcmp(&serv_addr, &tmp_addr, sizeof(struct sockaddr_in)) == 0); 103cf9b1199SSargun Dhillon 1043677d0a1SDaniel T. Lee cleanup: 1053677d0a1SDaniel T. Lee bpf_link__destroy(link); 1063677d0a1SDaniel T. Lee bpf_object__close(obj); 107cf9b1199SSargun Dhillon return 0; 108cf9b1199SSargun Dhillon } 109