问题
Scenario:
I've created SCTP one-to-many socket (functions that starts with big letter call corresponding standard functions with check for error and print errno to stderr)
int sock_fd,msg_flags;
char readbuf[BUFFSIZE];
struct sockaddr_in servaddr, cliaddr;
struct sctp_sndrcvinfo sri;
struct sctp_event_subscribe evnts;
int stream_increment=1;
socklen_t len;
size_t rd_sz;
sock_fd = Socket( AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
bzero( &servaddr, sizeof( servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl( INADDR_ANY);
servaddr.sin_port = htons( SERV_PORT);
Bind( sock_fd, ( SA *) &servaddr, sizeof(servaddr));
bzero( &evnts, sizeof( evnts));
evnts.sctp_data_io_event = 1;
Setsockopt( sock_fd, IPPROTO_SCTP, SCTP_EVENTS, &evnts, sizeof( evnts));
Listen( sock_fd, LISTENQ);
Then I block in a call to sctp_recvmsg to read a message when it arrives
rd_sz = Sctp_recvmsg( sock_fd, readbuf, sizeof( readbuf),
(SA *)&cliaddr, &len, &sri,&msg_flags);
And after client connects I call getsockopt to retrieve the current state of an SCTP associations
len = sizeof(struct sockaddr_in);
socklen_t retsz;
struct sctp_status status;
retsz = sizeof(status);
bzero(&status,sizeof(status));
status.sstat_assoc_id = sctp_address_to_associd(sock_fd, (SA *)&cliaddr, len);
getsockopt( sock_fd, IPPROTO_SCTP, SCTP_STATUS, &status, &retsz);
function sctp_address_to_associd is:
sctp_assoc_t
sctp_address_to_associd(int sock_fd, struct sockaddr *sa, socklen_t salen)
{
struct sctp_paddrparams sp;
socklen_t siz;
siz = sizeof(struct sctp_paddrparams);
bzero(&sp,siz);
memcpy(&sp.spp_address,sa,salen);
sctp_opt_info(sock_fd,0,
SCTP_PEER_ADDR_PARAMS, &sp, &siz);
return(sp.spp_assoc_id);
}
Why getsockopt returns "Invalid argument"? errno = 22. OS is Linux Ubuntu 12.10.
回答1:
The SCTP_PEER_ADDR_PARAMS socket option in the sctp_address_to_associd()
function cannot be used to learn the association id, at least not on linux.
Since you already get the association id from the sctp_recvmsg() call, use the association id of the struct sctp_sndrcvinfo
instead:
status.sstat_assoc_id = sri.sinfo_assoc_id;
getsockopt( sock_fd, IPPROTO_SCTP, SCTP_STATUS, &status, &retsz);
来源:https://stackoverflow.com/questions/23897781/getsockopt-invalid-argument-for-ipproto-sctp-sctp-status