On Sat, Sep 13, 2008 at 9:46 PM, Tom=E1s =D3 h=C9ilidhe <toe_list@lavabit.c=
om> wrote:
>
> Anyone know what's the most portable C networking library to use for
> sending custom frames? By "custom frames", I mean having the ability to
> write the entire frame all by yourself (I think some people use the term
> "raw sockets" to refer to this). For instance, here's a DNS request:
>
> unsigned char frame[] =3D
>    {
>      /* Offset 0 : Beginning of Ethernet frame */
>
>      0x00,0x03,0x6f,0x23,0x25,0x4a,  /* Destination MAC */
>      0x00,0x40,0x12,0x1b,0x77,0x36,  /* Source  MAC */
>                          0x08,0x00,  /* Protocol =3D=3D IP */
>
>      /* Offset 14 : Beginning of IP packet */
>
>      0x45,        /* IP Version and header length */
>      0x00,        /* TOS */
>      0x00,0x3c,   /* Total Length */
>      0x00,0x00,   /* Identification */
>      0x40,0x00,   /* Flags and Fragment Offset */
>      0x40,        /* Time To Live */
>      0x11,        /* Transport Layer Protocol =3D=3D UDP */
>
>      0,0,         /* IP Header Checksum */
>
>      192,168,0,55,     /* Source IP */
>      208,67,222,222,     /* Destination IP */
>
>      /* Offset 34 : Beginning of UDP segment */
>
>      0x80,0x01,   /* Source port */
>      0x00,0x35,   /* Destination port */
>      0x00,0x28,   /* Length of UDP segment (header + data) */
>      0x00,0x00,   /* Checksum */
>
>      /* Offset 42 : Beginning of DNS datagram */
>
>      0x22,0xf4,  /* Transaction ID */
>      0x01,0x00,  /* Flags */
>      0x00,0x01,  /* Questions */
>      0x00,0x00,  /* Answer RR's */
>      0x00,0x00,  /* Athority RR's */
>      0x00,0x00,  /* Additional RR's */
>
>      3,'w','w','w',6,'g','o','o','g','l','e',3,'c','o','m',0,
>
>      0x00,0x01,   /* Type A (Host Address) */
>      0x00,0x01    /* Class IN */
>    };
>
> At the moment I'm using Berkeley Sockets for sending custom frames, but
> I'm not sure if it's the best library to be using. I'd like if my
> program worked on stuff like Windows, Linux, Mac, Solaris, but it'd be a
> bonus if it worked on stuff like XBox and Playstation 3 aswell! Here's
> how I use Berkeley Sockets to send custom frames:
>
> First of all, I open a "raw socket":
>
>    int s =3D socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
>
> Next, I have to get a handle to the network card. Let's say that the
> network card is called "wlan0":
>
>    struct sockaddr_ll nic_dev =3D {0};
>    struct ifreq card =3D {0};
>    strcpy(card.ifr_name, "wlan0");
>    ioctl(s, SIOCGIFINDEX, &card);
>    nic_dev.sll_ifindex =3D card.ifr_ifindex;
>
> Next when I want to send a frame, all I have to do is:
>
>    sendto(s, &frame, sizeof frame, 0, (struct sockaddr
> const*)&nic_dev,sizeof nic_dev);
>
> Is there anything better than Berkeley Socket for sending custom frames?
> Anything more portable? Or is there a better way of using Berkeley
> sockets than the way I've shown above?
>
> --
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>

I ran into this a little while back and the code at this link was very help=
ful

http://www.codeproject.com/KB/IP/sendrawpacket.aspx

BTW: All the folks who had comments about comments on the code you
guys really need to write some more code :-), this is prototype code
that tamas was after and I could read it just fine :-)

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