SOCK_STREAM, SOCK_DGRAM, SOCK_RAW etc. Which one did you use ?
Based on the type of the socket functions like tcp_recvmsg, udp_recvmsg etc are called
from sock_recvmsg when it calls sock->ops->recvmsg(). So you may want to look at those
functions to know what is happening.
Hope this Helps, Rithin.
TI8 Benjamin Kohler wrote:
hi,
i just wrote a kernel module which sends some data to a server. after the server has received the data it sends back some data to the kernel module. sending data from the module to the server works! but i cant get the response sent by the server. for receiving data within my kernel module i use the sock_recvmsg function. the return value is always 0. does anybody know how i have exactly to use this function so that i can receive any data within my kernel module
here is my Send_Msg function within my Kernel Module:
int Send_Msg(const char *buffer) { struct msghdr send_msg; struct msghdr recv_msg; struct iovec iov; struct timeval now1; mm_segment_t oldfs; int error,i,len,lat; char recv_buf[1024]; int j = 0;
iov.iov_base=(void *)buffer; iov.iov_len=strlen(buffer); printk("<1>Size of Buffer in Send_Msg: %d\n", sizeof(buffer));
send_msg.msg_name=NULL; send_msg.msg_namelen=0; //sizeof(server); send_msg.msg_iov=&iov; send_msg.msg_iovlen=1; send_msg.msg_control=NULL; send_msg.msg_controllen=0; send_msg.msg_flags = 0;
do_gettimeofday(&now1);
oldfs = get_fs(); set_fs(KERNEL_DS); error = sock_sendmsg(Socket[0], &send_msg, (size_t)buffer); set_fs(oldfs);
iov.iov_base=(void *)recv_buf; iov.iov_len=sizeof(recv_buf);
recv_msg.msg_name=NULL; recv_msg.msg_namelen=0; //sizeof(server); recv_msg.msg_iov=&iov; recv_msg.msg_iovlen=1; recv_msg.msg_control=NULL; recv_msg.msg_controllen=0; recv_msg.msg_flags = 0;
udelay(1000);
oldfs = get_fs(); set_fs(KERNEL_DS); len = sock_recvmsg(Socket[0], &recv_msg, (size_t)recv_buf, MSG_WAITALL); set_fs(oldfs);
if (len<0) printk(KERN_ALERT "ERRO receive ########\n");
if (error<0) printk(KERN_ALERT "Erro send msg ERRO = %d buffer=%s\n",error,buffer);
printk("<1>recieved bytes: %d\n", len);
sock_release(Socket[0]); return 0; }
the sock_sendmsg works fine, but the sock_recvmsg() always seems to fail!!! Any help out there???
greetings benny
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