no such file or directory when using setsockopt(fd, SOL_TCP, MPTCP_SCHEDULER, scheduler, sizeof(scheduler))

[NotreDameDeParis]

I have installed mptcpv0.95 on both client(Ubuntu) and server(Ubuntu) successfully.But when I used the APIs mentioned in http://multipath-tcp.org/pmwiki.php/Users/ConfigureMPTCP,many errors occured. Problem 1: char *scheduler = "redundant"; setsockopt(fd, SOL_TCP, MPTCP_SCHEDULER, scheduler, sizeof(scheduler)); It turned back the erro "no such file or directory".

Problem2: getsockopt(..., ..., MPTCP_INFO, &minfo, sizeof(minfo)); It turned back the erro "bad address".

Can you please help me solve these problems or perhaps tell me why such errors occurred?

[matttbe]

Hi

It seems the wiki is down for the moment but are you sure it is what is written in the example?

char *scheduler = "redundant";
setsockopt(fd, SOL_TCP, MPTCP_SCHEDULER, scheduler, sizeof(scheduler));

Here sizeof(scheduler) will return 8, the size of a pointer on x86_64. While what you should write is the size of the array.

In other words, either you declare an array:

char scheduler[] = "redundant";

Or you give the correct number of chars:

setsockopt(fd, SOL_TCP, MPTCP_SCHEDULER, scheduler, strlen(scheduler) + 1);

For the second problem, we would need the entire code but I am sure this MPTCP_INFO code is well tested.

[NotreDameDeParis]

Thank you for your help and my first problem has been solved(just like what you told me). For the second problem. The entire code is here:

 struct mptcp_info minfo;
   struct mptcp_meta_info meta_info;
   struct tcp_info initial;
   struct tcp_info others[3];
   struct mptcp_sub_info others_info[3];

	minfo.tcp_info_len = sizeof(struct tcp_info);
	minfo.sub_len = sizeof(others);
	minfo.meta_len = sizeof(struct mptcp_meta_info);
	minfo.meta_info = &meta_info;
	minfo.initial = &initial;
	minfo.subflows = &others;
	minfo.sub_info_len = sizeof(struct mptcp_sub_info);
	minfo.total_sub_info_len = sizeof(others_info);
	minfo.subflow_info = &others_info;    
    
    int sockfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if(sockfd==-1)
	printf("\nsocket error");
    
    struct sockaddr_in serv_addr;
    memset(&serv_addr, 0, sizeof(serv_addr)); 
    serv_addr.sin_family = AF_INET;            
    serv_addr.sin_addr.s_addr = inet_addr("223.2.25.170"); 
    serv_addr.sin_port = htons(8080);

   char pathmanager[] = "fullmesh";
   int a =setsockopt(sockfd, SOL_TCP, MPTCP_PATH_MANAGER, pathmanager, sizeof(pathmanager));
   printf("\nfullmesh a=%d",a);

   char scheduler[] = "redundant";
   setsockopt(sockfd, SOL_TCP, MPTCP_SCHEDULER, scheduler, sizeof(scheduler));

   connect(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
   int enable=1;
   setsockopt(sockfd, SOL_TCP, MPTCP_ENABLED, &enable, sizeof(enable));

   m = getsockopt(sockfd, IPPROTO_TCP, MPTCP_INFO, &minfo, sizeof(minfo));
   if(m==-1)
{
	printf("\ncannot getsockopt(MPTCP_INFO)");
	 printf("\nerrno = %s\n",strerror(errno));
}

[matttbe]

Just to be sure, can you try:

m = getsockopt(sockfd, IPPROTO_TCP, MPTCP_INFO, &minfo, sizeof(minfo)*1000)

and also print:

printf("size: %zu, %zu\n", sizeof(minfo), sizeof(struct mptcp_info))

[NotreDameDeParis]

The size of minfo is 56 and the size of mptcp_info is also 56. The error also occurred.

[matttbe]

Not sure why you still have the issue with * 1000.

@cpaasch : any idea? :)

[cpaasch]

I will give it a shot later this week on v0.95.