/* data has been encrypted before */
static gint packet_send_out(PurpleConnection *gc, guint16 cmd, guint16 seq, guint8 *data, gint data_len)
{
qq_data *qd;
guint8 *buf;
gint buf_len;
gint bytes_sent;
g_return_val_if_fail(gc != NULL && gc->proto_data != NULL, -1);
qd = (qq_data *)gc->proto_data;
g_return_val_if_fail(data != NULL && data_len > 0, -1);
buf = g_newa(guint8, MAX_PACKET_SIZE);
memset(buf, 0, MAX_PACKET_SIZE);
/* encapsulate */
buf_len = packet_encap(qd, buf, MAX_PACKET_SIZE, cmd, seq, data, data_len);
if (buf_len <= 0) {
return -1;
}
qd->net_stat.sent++;
if (qd->use_tcp) {
bytes_sent = tcp_send_out(gc, buf, buf_len);
} else {
bytes_sent = udp_send_out(gc, buf, buf_len);
}
return bytes_sent;
}
int tcp_send_text(struct tcp_sock *tsk, void *buf, int len)
{
struct pkbuf *pkb;
int slen = 0;
int segsize = tsk->sk.sk_dst->rt_dev->net_mtu - IP_HRD_SZ - TCP_HRD_SZ;
len = min(len, (int)tsk->snd_wnd);
while (slen < len) {
/* TODO: handle silly window syndrome */
segsize = min(segsize, len - slen);
pkb = alloc_pkb(ETH_HRD_SZ + IP_HRD_SZ + TCP_HRD_SZ + segsize);
tcp_init_text(tsk, pkb, buf + slen, segsize);
slen += segsize;
if (slen >= len)
pkb2tcp(pkb)->psh = 1;
tcp_send_out(tsk, pkb, NULL);
}
/* zero window: request window update */
if (!slen) {
/* TODO: persist timer */
tcp_send_ack(tsk, NULL);
slen = -1;
}
return slen;
}
/*
* Reset algorithm is not stated directly in RFC 793,
* but we can conclude it according to all reset generation.
* NOTE: maybe @tsk is NULL
*/
void tcp_send_reset(struct tcp_sock *tsk, struct tcp_segment *seg)
{
struct tcp *otcp, *tcphdr = seg->tcphdr;
struct pkbuf *opkb;
if (tcphdr->rst)
return;
opkb = alloc_pkb(ETH_HRD_SZ + IP_HRD_SZ + TCP_HRD_SZ);
/* fill tcp head */
otcp = (struct tcp *)pkb2ip(opkb)->ip_data;
otcp->src = tcphdr->dst;
otcp->dst = tcphdr->src;
if (tcphdr->ack) {
/*
* Should we set ack?
* -Yes for xinu, it always set ack to seq+len
* +No for Linux
* +No for tapip
*/
otcp->seq = tcphdr->ackn;
} else {
otcp->ackn = _htonl(seg->seq + seg->len);
otcp->ack = 1;
}
otcp->doff = TCP_HRD_DOFF;
otcp->rst = 1;
tcpdbg("send RESET from "IPFMT":%d to "IPFMT":%d",
ipfmt(seg->iphdr->ip_dst), _ntohs(otcp->src),
ipfmt(seg->iphdr->ip_src), _ntohs(otcp->dst));
tcp_send_out(NULL, opkb, seg);
}
void tcp_send_fin(struct tcp_sock *tsk)
{
struct tcp *otcp;
struct pkbuf *opkb;
opkb = alloc_pkb(ETH_HRD_SZ + IP_HRD_SZ + TCP_HRD_SZ);
/* fill tcp head */
otcp = (struct tcp *)pkb2ip(opkb)->ip_data;
otcp->src = tsk->sk.sk_sport;
otcp->dst = tsk->sk.sk_dport;
otcp->doff = TCP_HRD_DOFF;
otcp->seq = _htonl(tsk->snd_nxt);
otcp->window = _htons(tsk->rcv_wnd);
otcp->fin = 1;
/*
* Should we send an ACK?
* Yes, tcp stack will drop packet if it has no ACK bit
* according to RFC 793 #SEGMENT RECEIVE
*/
otcp->ackn = _htonl(tsk->rcv_nxt);
otcp->ack = 1;
tcpdbg("send FIN(%u)/ACK(%u) [WIN %d] to "IPFMT":%d",
_ntohl(otcp->seq), _ntohl(otcp->ackn),
_ntohs(otcp->window), ipfmt(tsk->sk.sk_daddr),
_ntohs(otcp->dst));
tcp_send_out(tsk, opkb, NULL);
}
void tcp_send_synack(struct tcp_sock *tsk, struct tcp_segment *seg)
{
/*
* LISTEN :
* SYN-SENT:
* SEG: SYN, no ACK, no RST
* <SEQ=ISS><ACK=RCV.NXT><CTL=SYN,ACK>
* (ISS == SND.NXT)
*/
struct tcp *otcp, *tcphdr = seg->tcphdr;
struct pkbuf *opkb;
if (tcphdr->rst)
return;
opkb = alloc_pkb(ETH_HRD_SZ + IP_HRD_SZ + TCP_HRD_SZ);
/* fill tcp head */
otcp = (struct tcp *)pkb2ip(opkb)->ip_data;
otcp->src = tcphdr->dst;
otcp->dst = tcphdr->src;
otcp->doff = TCP_HRD_DOFF;
otcp->seq = _htonl(tsk->iss);
otcp->ackn = _htonl(tsk->rcv_nxt);
otcp->syn = 1;
otcp->ack = 1;
otcp->window = _htons(tsk->rcv_wnd);
tcpdbg("send SYN(%u)/ACK(%u) [WIN %d] to "IPFMT":%d",
_ntohl(otcp->seq), _ntohs(otcp->window),
_ntohl(otcp->ackn), ipfmt(seg->iphdr->ip_dst),
_ntohs(otcp->dst));
tcp_send_out(tsk, opkb, seg);
}
void tcp_send_syn(struct tcp_sock *tsk, struct tcp_segment *seg)
{
/*
* SYN-SENT:
*/
struct tcp *otcp;
struct pkbuf *opkb;
opkb = alloc_pkb(ETH_HRD_SZ + IP_HRD_SZ + TCP_HRD_SZ);
/* fill tcp head */
otcp = (struct tcp *)pkb2ip(opkb)->ip_data;
otcp->src = tsk->sk.sk_sport;
otcp->dst = tsk->sk.sk_dport;
otcp->doff = TCP_HRD_DOFF;
otcp->seq = _htonl(tsk->iss);
otcp->syn = 1;
otcp->window = _htons(tsk->rcv_wnd);
tcpdbg("send SYN(%u) [WIN %d] to "IPFMT":%d",
_ntohl(otcp->seq), _ntohs(otcp->window),
ipfmt(tsk->sk.sk_daddr), _ntohs(otcp->dst));
tcp_send_out(tsk, opkb, seg);
}
/*
* Acknowledgment algorithm is not stated directly in RFC 793,
* but we can conclude it from all acknowledgment situation.
*/
void tcp_send_ack(struct tcp_sock *tsk, struct tcp_segment *seg)
{
/*
* SYN-SENT :
* SEG: SYN, acceptable ACK, no RST (SND.NXT = SEG.SEQ+1)
* <SEQ=SND.NXT><ACK=RCV.NXT><CTL=ACK>
* SYN-RECEIVED / ESTABLISHED / FIN-WAIT-1 / FIN-WAIT-2 /
* CLOSE-WAIT / CLOSING / LAST-ACK / TIME-WAIT :
* SEG: no RST, ??ACK, ??SYN (segment is not acceptable)
* <SEQ=SND.NXT><ACK=RCV.NXT><CTL=ACK>
* ESTABLISHED / FIN-WAIT-1 / FIN-WAIT-2 / process the segment text:
* SEG: ACK, no RST
* <SEQ=SND.NXT><ACK=RCV.NXT><CTL=ACK>
* (This acknowledgment should be piggybacked on a segment being
* transmitted if possible without incurring undue delay.)
*/
struct tcp *otcp, *tcphdr = seg->tcphdr;
struct pkbuf *opkb;
if (tcphdr->rst)
return;
opkb = alloc_pkb(ETH_HRD_SZ + IP_HRD_SZ + TCP_HRD_SZ);
/* fill tcp head */
otcp = (struct tcp *)pkb2ip(opkb)->ip_data;
otcp->src = tcphdr->dst;
otcp->dst = tcphdr->src;
otcp->doff = TCP_HRD_DOFF;
otcp->seq = _htonl(tsk->snd_nxt);
otcp->ackn = _htonl(tsk->rcv_nxt);
otcp->ack = 1;
otcp->window = _htons(tsk->rcv_wnd);
tcpdbg("send ACK(%u) [WIN %d] to "IPFMT":%d",
_ntohl(otcp->ackn), _ntohs(otcp->window),
ipfmt(seg->iphdr->ip_src), _ntohs(otcp->dst));
tcp_send_out(tsk, opkb, seg);
}