This source file includes following definitions.
- open_port
- main
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9 #include <errno.h>
10 #include <error.h>
11 #include <arpa/inet.h>
12 #include <netinet/in.h>
13 #include <stdbool.h>
14 #include <stdio.h>
15 #include <sys/socket.h>
16 #include <sys/types.h>
17 #include <unistd.h>
18
19 #define PORT 9999
20
21 int open_port(int ipv6, int any)
22 {
23 int fd = -1;
24 int reuseaddr = 1;
25 int v6only = 1;
26 int addrlen;
27 int ret = -1;
28 struct sockaddr *addr;
29 int family = ipv6 ? AF_INET6 : AF_INET;
30
31 struct sockaddr_in6 addr6 = {
32 .sin6_family = AF_INET6,
33 .sin6_port = htons(PORT),
34 .sin6_addr = in6addr_any
35 };
36 struct sockaddr_in addr4 = {
37 .sin_family = AF_INET,
38 .sin_port = htons(PORT),
39 .sin_addr.s_addr = any ? htonl(INADDR_ANY) : inet_addr("127.0.0.1"),
40 };
41
42
43 if (ipv6) {
44 addr = (struct sockaddr*)&addr6;
45 addrlen = sizeof(addr6);
46 } else {
47 addr = (struct sockaddr*)&addr4;
48 addrlen = sizeof(addr4);
49 }
50
51 if ((fd = socket(family, SOCK_STREAM, IPPROTO_TCP)) < 0) {
52 perror("socket");
53 goto out;
54 }
55
56 if (ipv6 && setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, (void*)&v6only,
57 sizeof(v6only)) < 0) {
58 perror("setsockopt IPV6_V6ONLY");
59 goto out;
60 }
61
62 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &reuseaddr,
63 sizeof(reuseaddr)) < 0) {
64 perror("setsockopt SO_REUSEADDR");
65 goto out;
66 }
67
68 if (bind(fd, addr, addrlen) < 0) {
69 perror("bind");
70 goto out;
71 }
72
73 if (any)
74 return fd;
75
76 if (listen(fd, 1) < 0) {
77 perror("listen");
78 goto out;
79 }
80 return fd;
81 out:
82 close(fd);
83 return ret;
84 }
85
86 int main(void)
87 {
88 int listenfd;
89 int fd1, fd2;
90
91 fprintf(stderr, "Opening 127.0.0.1:%d\n", PORT);
92 listenfd = open_port(0, 0);
93 if (listenfd < 0)
94 error(1, errno, "Couldn't open listen socket");
95 fprintf(stderr, "Opening INADDR_ANY:%d\n", PORT);
96 fd1 = open_port(0, 1);
97 if (fd1 >= 0)
98 error(1, 0, "Was allowed to create an ipv4 reuseport on a already bound non-reuseport socket");
99 fprintf(stderr, "Opening in6addr_any:%d\n", PORT);
100 fd1 = open_port(1, 1);
101 if (fd1 < 0)
102 error(1, errno, "Couldn't open ipv6 reuseport");
103 fprintf(stderr, "Opening INADDR_ANY:%d\n", PORT);
104 fd2 = open_port(0, 1);
105 if (fd2 >= 0)
106 error(1, 0, "Was allowed to create an ipv4 reuseport on a already bound non-reuseport socket");
107 close(fd1);
108 fprintf(stderr, "Opening INADDR_ANY:%d after closing ipv6 socket\n", PORT);
109 fd1 = open_port(0, 1);
110 if (fd1 >= 0)
111 error(1, 0, "Was allowed to create an ipv4 reuseport on an already bound non-reuseport socket with no ipv6");
112 fprintf(stderr, "Success");
113 return 0;
114 }