好的，我终于解决了多宿主问题。这就是我所做的。
我使用sctp_paddrparams结构将心跳值调整为5000
ms。位于该结构中的flags变量必须处于SPP_HB_ENABLE模式下，因为否则，当尝试使用setsockopt（）设置值时，SCTP会忽略心跳值。
这就是SCTP不能像我所希望的那样频繁发送心跳的原因。我没注意到flag变量的原因是我正在阅读的SCTP的过时参考指南，该指南指出该结构内不存在flags变量！较新的参考资料显示存在。这样心跳问题就解决了！
另一件事是将rto_max值修改为例如2000毫秒左右。降低该值将指示SCTP更快地更改路径。默认值为60 000
ms，该值过高（开始更改路径前1分钟）。可以使用sctp_rtoinfo结构调整rto_max值。
通过这两个修改，多宿主开始工作。哦，另一件事。当服务器处于SEQPACKET模式时，客户端必须处于STREAM模式。客户端使用普通的send（）命令将数据发送到服务器，而服务器使用sctp_recvmsg（）读取数据，其中addr
struct设置为NULL。
我希望这些信息可以帮助其他在SCTP多宿主方面苦苦挣扎的人。欢呼大家的意见，对我来说是很大的帮助！这是一些代码示例，因此如果您问我，这可能是网络中的第一个多宿主简单示例（除了多流示例外，没有找到其他示例）
服务器：
#include <sys/types.h>#include <sys/socket.h>#include <signal.h>#include <netinet/in.h>#include <netinet/sctp.h>#include <arpa/inet.h>#include <string.h>#include <unistd.h>#include <stdio.h>#include <sys/ioctl.h>#include <net/if.h>#include <stdlib.h>#include <pthread.h>#define BUFFER_SIZE (1 << 16)#define PORT 10000int sock, ret, flags;int i, reuse = 1;int addr_count = 0;char buffer[BUFFER_SIZE];socklen_t from_len;struct sockaddr_in addr;struct sockaddr_in *laddr[10];struct sockaddr_in *paddrs[10];struct sctp_sndrcvinfo sinfo;struct sctp_event_subscribe event; struct sctp_prim prim_addr; struct sctp_paddrparams heartbeat;struct sigaction sig_handler;struct sctp_rtoinfo rtoinfo;void handle_signal(int signum);int main(void){ if((sock = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP)) < 0) perror("socket"); memset(&addr, 0, sizeof(struct sockaddr_in)); memset(&event, 1, sizeof(struct sctp_event_subscribe)); memset(&heartbeat, 0, sizeof(struct sctp_paddrparams)); memset(&rtoinfo, 0, sizeof(struct sctp_rtoinfo)); addr.sin_family = AF_INET; addr.sin_addr.s_addr = htonl(INADDR_ANY); addr.sin_port = htons(PORT); from_len = (socklen_t)sizeof(struct sockaddr_in); sig_handler.sa_handler = handle_signal; sig_handler.sa_flags = 0; heartbeat.spp_flags = SPP_HB_ENABLE; heartbeat.spp_hbinterval = 5000; heartbeat.spp_pathmaxrxt = 1; rtoinfo.srto_max = 2000; if(setsockopt(sock, SOL_SCTP, SCTP_PEER_ADDR_PARAMS , &heartbeat, sizeof(heartbeat)) != 0) perror("setsockopt"); if(setsockopt(sock, SOL_SCTP, SCTP_RTOINFO , &rtoinfo, sizeof(rtoinfo)) != 0) perror("setsockopt"); if(sigaction(SIGINT, &sig_handler, NULL) == -1) perror("sigaction"); if(setsockopt(sock, IPPROTO_SCTP, SCTP_EVENTS, &event, sizeof(struct sctp_event_subscribe)) < 0) perror("setsockopt"); if(setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(int))< 0) perror("setsockopt"); if(bind(sock, (struct sockaddr*)&addr, sizeof(struct sockaddr)) < 0) perror("bind"); if(listen(sock, 2) < 0) perror("listen"); i = (sizeof heartbeat); getsockopt(sock, SOL_SCTP, SCTP_PEER_ADDR_PARAMS, &heartbeat, (socklen_t*)&i); printf("Heartbeat interval %dn", heartbeat.spp_hbinterval); addr_count = sctp_getladdrs(sock, 0, (struct sockaddr**)laddr); printf("Addresses binded: %dn", addr_count); for(i = 0; i < addr_count; i++) printf("Address %d: %s:%dn", i +1, inet_ntoa((*laddr)[i].sin_addr), (*laddr)[i].sin_port); sctp_freeladdrs((struct sockaddr*)*laddr); while(1) { flags = 0; ret = sctp_recvmsg(sock, buffer, BUFFER_SIZE, NULL, 0, NULL, &flags); if(flags & MSG_NOTIFICATION) printf("Notification received from %s:%un", inet_ntoa(addr.sin_addr), ntohs(addr.sin_port)); printf("%d bytes received from %s:%un", ret, inet_ntoa(addr.sin_addr), ntohs(addr.sin_port)); } if(close(sock) < 0) perror("close");}void handle_signal(int signum){ switch(signum) { case SIGINT: if(close(sock) != 0) perror("close"); exit(0); break; default: exit(0); break; }}客户：
#include <sys/types.h>#include <sys/socket.h>#include <signal.h>#include <netinet/in.h>#include <netinet/sctp.h>#include <arpa/inet.h>#include <string.h>#include <unistd.h>#include <stdio.h>#include <stdlib.h>#include <sys/ioctl.h>#define PORT 11000#define MSG_SIZE 1000#define NUMBER_OF_MESSAGES 1000int sock;struct sockaddr_in *paddrs[5];struct sockaddr_in *laddrs[5];void handle_signal(int signum);int main(int argc, char **argv){ int i; int counter = 0; int asconf = 1; int ret; int addr_count; char address[16]; char buffer[MSG_SIZE]; sctp_assoc_t id; struct sockaddr_in addr; struct sctp_status status; struct sctp_initmsg initmsg; struct sctp_event_subscribe events; struct sigaction sig_handler; struct sctp_paddrparams heartbeat; struct sctp_rtoinfo rtoinfo; memset(&buffer, 'j', MSG_SIZE); memset(&initmsg, 0, sizeof(struct sctp_initmsg)); memset(&addr, 0, sizeof(struct sockaddr_in)); memset(&events, 1, sizeof(struct sctp_event_subscribe)); memset(&status, 0, sizeof(struct sctp_status)); memset(&heartbeat, 0, sizeof(struct sctp_paddrparams)); memset(&rtoinfo, 0, sizeof(struct sctp_rtoinfo)) if(argc != 2 || (inet_addr(argv[1]) == -1)) { puts("Usage: client [IP ADDRESS in form xxx.xxx.xxx.xxx] "); return 0; } strncpy(address, argv[1], 15); address[15] = 0; addr.sin_family = AF_INET; inet_aton(address, &(addr.sin_addr)); addr.sin_port = htons(PORT); initmsg.sinit_num_ostreams = 2; initmsg.sinit_max_instreams = 2; initmsg.sinit_max_attempts = 1; heartbeat.spp_flags = SPP_HB_ENABLE; heartbeat.spp_hbinterval = 5000; heartbeat.spp_pathmaxrxt = 1; rtoinfo.srto_max = 2000; sig_handler.sa_handler = handle_signal; sig_handler.sa_flags = 0; if(sigaction(SIGINT, &sig_handler, NULL) == -1) perror("sigaction"); if((ret = (sock = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP))) < 0) perror("socket"); if((ret = setsockopt(sock, SOL_SCTP, SCTP_PEER_ADDR_PARAMS , &heartbeat, sizeof(heartbeat))) != 0) perror("setsockopt"); if((ret = setsockopt(sock, SOL_SCTP, SCTP_RTOINFO , &rtoinfo, sizeof(rtoinfo))) != 0) perror("setsockopt"); if((ret = setsockopt(sock, SOL_SCTP, SCTP_INITMSG, &initmsg, sizeof(initmsg))) != 0) perror("setsockopt"); if((ret = setsockopt(sock, SOL_SCTP, SCTP_EVENTS, (void *)&events, sizeof(events))) != 0) perror("setsockopt"); i = (sizeof heartbeat); getsockopt(sock, SOL_SCTP, SCTP_PEER_ADDR_PARAMS, &heartbeat, (socklen_t*)&i); printf("Heartbeat interval %dn", heartbeat.spp_hbinterval); if(((ret = connect(sock, (struct sockaddr*)&addr, sizeof(struct sockaddr)))) < 0) { perror("connect"); close(sock); exit(0); } addr_count = sctp_getpaddrs(sock, 0, (struct sockaddr**)paddrs); printf("nPeer addresses: %dn", addr_count); for(i = 0; i < addr_count; i++) printf("Address %d: %s:%dn", i +1, inet_ntoa((*paddrs)[i].sin_addr), (*paddrs)[i].sin_port); sctp_freepaddrs((struct sockaddr*)*paddrs); for(i = 0; i < NUMBER_OF_MESSAGES; i++) { counter++; printf("Sending data chunk #%d...", counter); if((ret = send(sock, buffer, MSG_SIZE, 0)) == -1) perror("write"); printf("Sent %d bytes to peern",ret); sleep(1); } if(close(sock) != 0) perror("close");}void handle_signal(int signum){ switch(signum) { case SIGINT: if(close(sock) != 0) perror("close"); exit(0); break; default: exit(0); break; }}
