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
main(int ac,char ** argv)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
27*d4fffba4SDaniel T. Lee snprintf(filename, sizeof(filename), "%s.bpf.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