ptpd2提示failed to join the multicast group (strerror: No buffer space available)

下载交叉编译ptpd-ptpd-2.3.1源码，在IMX6板子上面运行ptpd2提示错误如下：

root@imx6qsabresd_genvict:~# ./ptpd2 -C -m -i eth0
2023-11-24 14:30:21.484399 ptpd2[6512].startup (info)      (___) Configuration OK
2023-11-24 14:30:21.487152 ptpd2[6512].startup (info)      (___) Successfully acquired lock on /var/run/ptpd2.lock
2023-11-24 14:30:21.487684 ptpd2[6512].startup (notice)    (___) PTPDv2 started successfully on eth0 using "masterslave" preset (PID 6512)
2023-11-24 14:30:21.487775 ptpd2[6512].startup (info)      (___) TimingService.PTP0: PTP service init
2023-11-24 14:30:21.491781 ptpd2[6512].eth0 (error)     (init) failed to join the multicast group      (strerror: No buffer space available)
2023-11-24 14:30:21.491880 ptpd2[6512].eth0 (error)     (init) Failed to initialize network
2023-11-24 14:30:21.491943 ptpd2[6512].eth0 (error)     (flt) PTPd init failed - will retry in 10 seconds

查看源码：src/dep/net.c，函数：netInitMulticastIPv4

	/* join multicast group (for receiving) on specified interface */if (setsockopt(netPath->eventSock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &imr, sizeof(struct ip_mreq)) < 0|| setsockopt(netPath->generalSock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &imr, sizeof(struct ip_mreq)) < 0) {PERROR("failed to join the multicast group");return FALSE;}

添加错误值打印：

	int ret1=0;int ret2=0;ret1=setsockopt(netPath->eventSock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &imr, sizeof(struct ip_mreq));if(ret1 < 0){printf("errno = %d\n",errno);	//105	printf("ret1=%d\n",ret1);return FALSE;}ret2=setsockopt(netPath->generalSock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &imr, sizeof(struct ip_mreq));if(ret2 < 0){printf("ret2=%d\n",ret2);return FALSE;}

setsockopt返回-1，错误值105，搜索系统头文件：/usr/include/asm-generic/errno.h

#define ENOBUFS     105 /* No buffer space available */

通过网上搜到https://www.jianshu.com/p/6dfaeefac922，UDP组播的内核参数为0导致问题，修改10解决问题：

root@imx6qsabresd_genvict:~# sysctl net.ipv4.igmp_max_memberships
net.ipv4.igmp_max_memberships = 0
root@imx6qsabresd_genvict:~# 
root@imx6qsabresd_genvict:~# sysctl -w net.ipv4.igmp_max_memberships=10
net.ipv4.igmp_max_memberships = 10

查看其他平台是设置的参数20，所以没有这个问题。