write() function - no such device or address

hi!
i want to know how to build my own packets.
especially arp packets.

here is my code for now

Code:

struct arppacket
{
...
...
} pseudoarp;

...
...
//every member is filled with the needed infos

sockfd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));

write(sockfd, (struct arppacket *)&pseudarp, sizeof((struct arppacket *)&pseudoarp));

//when i do error checking on the write function
//it give me "no such device or address"
...

i checked the infos i filled the structure members with, and they were correct.
what could be my problem?

thank you!

Did you error check the return from the socket() call?

Also, this is incorrect:
>>sizeof((struct arppacket *)&pseudoarp)
You are meant to pass the number of bytes you want to send, so I guess you're wanting something more like this:
>>sizeof(pseudoarp)

>write(sockfd, (struct arppacket *)&pseudarp, sizeof((struct arppacket *)&pseudoarp));
should this not be like:

Code:

write(sockfd, (struct arppacket *)&pseudarp, sizeof(pseudoarp));

???

The sizeof() in your case will always return the same number irrespective of the members in it, because you are getting the size of the Pointer variable, which will be constant on your machine for any given dat type. Instead, sizeof(pseudoarp) gives you the right number of bytes used for this structure instance.

thanks for your replies.

i figured it out with the sendto() call.