static void tftp_send_next_block(struct tftp_session *spt, struct tftp_t *recv_tp) { struct sockaddr_in saddr, daddr; struct mbuf *m; struct tftp_t *tp; int nobytes; m = m_get(spt->slirp); if (!m) { return; } memset(m->m_data, 0, m->m_size); m->m_data += IF_MAXLINKHDR; tp = (void *)m->m_data; m->m_data += sizeof(struct udpiphdr); tp->tp_op = htons(TFTP_DATA); tp->x.tp_data.tp_block_nr = htons((spt->block_nr + 1) & 0xffff); saddr.sin_addr = recv_tp->ip.ip_dst; saddr.sin_port = recv_tp->udp.uh_dport; daddr.sin_addr = spt->client_ip; daddr.sin_port = spt->client_port; nobytes = tftp_read_data(spt, spt->block_nr, tp->x.tp_data.tp_buf, 512); if (nobytes < 0) { m_free(m); /* send "file not found" error back */ tftp_send_error(spt, 1, "File not found", tp); return; } m->m_len = sizeof(struct tftp_t) - (512 - nobytes) - sizeof(struct ip) - sizeof(struct udphdr); udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY); if (nobytes == 512) { tftp_session_update(spt); } else { tftp_session_terminate(spt); } spt->block_nr++; }