/*
 * Packet construction functions. Mostly shared between SSH-1 and SSH-2.
 */
static void ssh_pkt_ensure(struct Packet *pkt, int length)
{
    if (pkt->maxlen < length) {
	unsigned char *body = pkt->body;
	int offset = body ? body - pkt->data : 0;
	pkt->maxlen = length + 256;
	pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char);
	if (body) pkt->body = pkt->data + offset;
    }
}
static void ssh_pkt_adddata(struct Packet *pkt, void *data, int len)
{

#define ssh2_pkt_addstring_str(pkt, data) ssh_pkt_addstring_str(pkt, data)
#define ssh2_pkt_addstring_data(pkt, data, len) ssh_pkt_addstring_data(pkt, data, len)
#define ssh2_pkt_addstring(pkt, data) ssh_pkt_addstring(pkt, data)

static struct Packet *ssh2_pkt_init(int pkt_type)
{
    struct Packet *pkt = ssh_new_packet();
    pkt->length = 5; /* space for packet length + padding length */
    pkt->forcepad = 0;
    ssh_pkt_addbyte(pkt, (unsigned char) pkt_type);
    pkt->body = pkt->data + pkt->length; /* after packet type */
    return pkt;
}

/*
 * Construct an SSH-2 final-form packet: compress it, encrypt it,
 * put the MAC on it. Final packet, ready to be sent, is stored in
 * pkt->data. Total length is returned.