kengo sakai wrote:
> Hi,
>
> I am tring to set a flow label in IPv6 TCP message which TCP server send.
> I could set a flow label in IPv6 TCP message which TCP client send.
> Does anyone know how to set a flow label in IPv6 TCP server?
>
> There seems to be no documentation available about IPv6 flow lable in Linux.
>
> Attached you can find my simple TCP server program, which does not compile.
> Of course I don't expect you to debug my code,
> but I suppose it may be helpful.
>
> Regards,
> Kengo
>
> // tcpserver6.c
> #include <sys/types.h>
> #include <sys/socket.h>
> #include <netdb.h>
> #include <string.h>
> #include <unistd.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <errno.h>
>
> #define BACKLOG 5
> #define PORT "12345"
>
> int tcp_listen(const char* service) {
> int err;
> struct addrinfo hints;
> struct addrinfo* res = NULL;
> struct addrinfo* ai;
> int sockfd;
>
> memset(&hints, 0, sizeof(hints));
> hints.ai_family = AF_INET6;
> hints.ai_socktype = SOCK_STREAM;
> hints.ai_flags = AI_PASSIVE;
>
> err = getaddrinfo(NULL, service, &hints, &res);
> if (err != 0) {
> printf("getaddrinfo(): %s\n", gai_strerror(err));
> return -1;
> }
>
> ai = res;
> sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
> if (sockfd < 0)
> return -1;
>
> if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)
> return -1;
>
> if (listen(sockfd, BACKLOG) < 0)
> return -1;
>
> freeaddrinfo(res);
> return sockfd;
> }
>
> int main() {
> int sockfd;
>
> sockfd = tcp_listen(PORT);
> if (sockfd < 0) {
> perror("server");
> exit(1);
> }
>
> printf("wait...\n");
>
> while (1) {
> int cs;
> struct sockaddr_storage sa;
> socklen_t len = sizeof(sa);
> cs = accept(sockfd, (struct sockaddr*) &sa, &len);
> if (cs < 0) {
> if (errno == EINTR)
> continue;
> perror("accept");
> exit(1);
> }
>
> printf("accepted.\n");
>
> char ch;
>
> (void)set_flow_label(cs, &sa);
> read(cs, &ch, 1);
> write(cs, &ch, 1); // I expect that the flowlabel is set to the packet.
>
> close(cs);
> }
> return 0;
> }
> // tcpserver6.c end
>
> // flowlabel.c
> #include <sys/socket.h>
> #include <linux/in.h>
> #include <linux/in6.h>
> #include <string.h>
> #include <stdio.h>
> #include <errno.h>
>
> int set_flow_label(int sock, struct sockaddr_in6 *addr)
> {
> char freq_buf[sizeof(struct in6_flowlabel_req)];
> struct in6_flowlabel_req *freq = (struct in6_flowlabel_req *)freq_buf;
> int freq_len = sizeof(*freq);
> int on = 1;
>
> if (setsockopt(sock, IPPROTO_IPV6, IPV6_FLOWINFO_SEND,
> &on, sizeof(on)) == -1) {
> printf("setsockopt: %s\n", strerror(errno));
> return 1;
> }
>
> memset(freq, 0, sizeof(*freq));
> freq->flr_label = 0;
> freq->flr_action = IPV6_FL_A_GET;
> freq->flr_flags = IPV6_FL_F_CREATE;
> freq->flr_share = IPV6_FL_S_EXCL;
> memcpy(&freq->flr_dst, &addr->sin6_addr, 16);
> if (setsockopt(sock, IPPROTO_IPV6, IPV6_FLOWLABEL_MGR, freq, freq_len)
> == -1) {
> printf("setsockopt: %s\n", strerror(errno));
> return 1;
> }
> return 0;
> }
> // flowlabel.c end
> --
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>
>
It compiled just fine, without edits, for me.
LDB
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