| /* |
| * Copyright (c) 1995 Danny Gasparovski. |
| * |
| * Please read the file COPYRIGHT for the |
| * terms and conditions of the copyright. |
| */ |
| |
| #include <slirp.h> |
| |
| int if_mtu, if_mru; |
| int if_comp; |
| int if_maxlinkhdr; |
| int if_queued = 0; /* Number of packets queued so far */ |
| int if_thresh = 10; /* Number of packets queued before we start sending |
| * (to prevent allocing too many mbufs) */ |
| |
| struct mbuf if_fastq; /* fast queue (for interactive data) */ |
| struct mbuf if_batchq; /* queue for non-interactive data */ |
| struct mbuf *next_m; /* Pointer to next mbuf to output */ |
| |
| #define ifs_init(ifm) ((ifm)->ifs_next = (ifm)->ifs_prev = (ifm)) |
| |
| void |
| ifs_insque(ifm, ifmhead) |
| struct mbuf *ifm, *ifmhead; |
| { |
| ifm->ifs_next = ifmhead->ifs_next; |
| ifmhead->ifs_next = ifm; |
| ifm->ifs_prev = ifmhead; |
| ifm->ifs_next->ifs_prev = ifm; |
| } |
| |
| void |
| ifs_remque(ifm) |
| struct mbuf *ifm; |
| { |
| ifm->ifs_prev->ifs_next = ifm->ifs_next; |
| ifm->ifs_next->ifs_prev = ifm->ifs_prev; |
| } |
| |
| void |
| if_init() |
| { |
| #if 0 |
| /* |
| * Set if_maxlinkhdr to 48 because it's 40 bytes for TCP/IP, |
| * and 8 bytes for PPP, but need to have it on an 8byte boundary |
| */ |
| #ifdef USE_PPP |
| if_maxlinkhdr = 48; |
| #else |
| if_maxlinkhdr = 40; |
| #endif |
| #else |
| /* 14 for ethernet + 40 */ |
| if_maxlinkhdr = 14 + 40; |
| #endif |
| if_mtu = 1500; |
| if_mru = 1500; |
| if_comp = IF_AUTOCOMP; |
| if_fastq.ifq_next = if_fastq.ifq_prev = &if_fastq; |
| if_batchq.ifq_next = if_batchq.ifq_prev = &if_batchq; |
| // sl_compress_init(&comp_s); |
| next_m = &if_batchq; |
| } |
| |
| #if 0 |
| /* |
| * This shouldn't be needed since the modem is blocking and |
| * we don't expect any signals, but what the hell.. |
| */ |
| inline int |
| writen(fd, bptr, n) |
| int fd; |
| char *bptr; |
| int n; |
| { |
| int ret; |
| int total; |
| |
| /* This should succeed most of the time */ |
| ret = write(fd, bptr, n); |
| if (ret == n || ret <= 0) |
| return ret; |
| |
| /* Didn't write everything, go into the loop */ |
| total = ret; |
| while (n > total) { |
| ret = write(fd, bptr+total, n-total); |
| if (ret <= 0) |
| return ret; |
| total += ret; |
| } |
| return total; |
| } |
| |
| /* |
| * if_input - read() the tty, do "top level" processing (ie: check for any escapes), |
| * and pass onto (*ttyp->if_input) |
| * |
| * XXXXX Any zeros arriving by themselves are NOT placed into the arriving packet. |
| */ |
| #define INBUFF_SIZE 2048 /* XXX */ |
| void |
| if_input(ttyp) |
| struct ttys *ttyp; |
| { |
| u_char if_inbuff[INBUFF_SIZE]; |
| int if_n; |
| |
| DEBUG_CALL("if_input"); |
| DEBUG_ARG("ttyp = %lx", (long)ttyp); |
| |
| if_n = read(ttyp->fd, (char *)if_inbuff, INBUFF_SIZE); |
| |
| DEBUG_MISC((dfd, " read %d bytes\n", if_n)); |
| |
| if (if_n <= 0) { |
| if (if_n == 0 || (errno != EINTR && errno != EAGAIN)) { |
| if (ttyp->up) |
| link_up--; |
| tty_detached(ttyp, 0); |
| } |
| return; |
| } |
| if (if_n == 1) { |
| if (*if_inbuff == '0') { |
| ttyp->ones = 0; |
| if (++ttyp->zeros >= 5) |
| slirp_exit(0); |
| return; |
| } |
| if (*if_inbuff == '1') { |
| ttyp->zeros = 0; |
| if (++ttyp->ones >= 5) |
| tty_detached(ttyp, 0); |
| return; |
| } |
| } |
| ttyp->ones = ttyp->zeros = 0; |
| |
| (*ttyp->if_input)(ttyp, if_inbuff, if_n); |
| } |
| #endif |
| |
| /* |
| * if_output: Queue packet into an output queue. |
| * There are 2 output queue's, if_fastq and if_batchq. |
| * Each output queue is a doubly linked list of double linked lists |
| * of mbufs, each list belonging to one "session" (socket). This |
| * way, we can output packets fairly by sending one packet from each |
| * session, instead of all the packets from one session, then all packets |
| * from the next session, etc. Packets on the if_fastq get absolute |
| * priority, but if one session hogs the link, it gets "downgraded" |
| * to the batchq until it runs out of packets, then it'll return |
| * to the fastq (eg. if the user does an ls -alR in a telnet session, |
| * it'll temporarily get downgraded to the batchq) |
| */ |
| void |
| if_output(so, ifm) |
| struct socket *so; |
| struct mbuf *ifm; |
| { |
| struct mbuf *ifq; |
| int on_fastq = 1; |
| |
| DEBUG_CALL("if_output"); |
| DEBUG_ARG("so = %lx", (long)so); |
| DEBUG_ARG("ifm = %lx", (long)ifm); |
| |
| /* |
| * First remove the mbuf from m_usedlist, |
| * since we're gonna use m_next and m_prev ourselves |
| * XXX Shouldn't need this, gotta change dtom() etc. |
| */ |
| if (ifm->m_flags & M_USEDLIST) { |
| remque(ifm); |
| ifm->m_flags &= ~M_USEDLIST; |
| } |
| |
| /* |
| * See if there's already a batchq list for this session. |
| * This can include an interactive session, which should go on fastq, |
| * but gets too greedy... hence it'll be downgraded from fastq to batchq. |
| * We mustn't put this packet back on the fastq (or we'll send it out of order) |
| * XXX add cache here? |
| */ |
| for (ifq = if_batchq.ifq_prev; ifq != &if_batchq; ifq = ifq->ifq_prev) { |
| if (so == ifq->ifq_so) { |
| /* A match! */ |
| ifm->ifq_so = so; |
| ifs_insque(ifm, ifq->ifs_prev); |
| goto diddit; |
| } |
| } |
| |
| /* No match, check which queue to put it on */ |
| if (so && (so->so_iptos & IPTOS_LOWDELAY)) { |
| ifq = if_fastq.ifq_prev; |
| on_fastq = 1; |
| /* |
| * Check if this packet is a part of the last |
| * packet's session |
| */ |
| if (ifq->ifq_so == so) { |
| ifm->ifq_so = so; |
| ifs_insque(ifm, ifq->ifs_prev); |
| goto diddit; |
| } |
| } else |
| ifq = if_batchq.ifq_prev; |
| |
| /* Create a new doubly linked list for this session */ |
| ifm->ifq_so = so; |
| ifs_init(ifm); |
| insque(ifm, ifq); |
| |
| diddit: |
| ++if_queued; |
| |
| if (so) { |
| /* Update *_queued */ |
| so->so_queued++; |
| so->so_nqueued++; |
| /* |
| * Check if the interactive session should be downgraded to |
| * the batchq. A session is downgraded if it has queued 6 |
| * packets without pausing, and at least 3 of those packets |
| * have been sent over the link |
| * (XXX These are arbitrary numbers, probably not optimal..) |
| */ |
| if (on_fastq && ((so->so_nqueued >= 6) && |
| (so->so_nqueued - so->so_queued) >= 3)) { |
| |
| /* Remove from current queue... */ |
| remque(ifm->ifs_next); |
| |
| /* ...And insert in the new. That'll teach ya! */ |
| insque(ifm->ifs_next, &if_batchq); |
| } |
| } |
| |
| #ifndef FULL_BOLT |
| /* |
| * This prevents us from malloc()ing too many mbufs |
| */ |
| if (link_up) { |
| /* if_start will check towrite */ |
| if_start(); |
| } |
| #endif |
| } |
| |
| /* |
| * Send a packet |
| * We choose a packet based on it's position in the output queues; |
| * If there are packets on the fastq, they are sent FIFO, before |
| * everything else. Otherwise we choose the first packet from the |
| * batchq and send it. the next packet chosen will be from the session |
| * after this one, then the session after that one, and so on.. So, |
| * for example, if there are 3 ftp session's fighting for bandwidth, |
| * one packet will be sent from the first session, then one packet |
| * from the second session, then one packet from the third, then back |
| * to the first, etc. etc. |
| */ |
| void |
| if_start(void) |
| { |
| struct mbuf *ifm, *ifqt; |
| |
| DEBUG_CALL("if_start"); |
| |
| if (if_queued == 0) |
| return; /* Nothing to do */ |
| |
| again: |
| /* check if we can really output */ |
| if (!slirp_can_output()) |
| return; |
| |
| /* |
| * See which queue to get next packet from |
| * If there's something in the fastq, select it immediately |
| */ |
| if (if_fastq.ifq_next != &if_fastq) { |
| ifm = if_fastq.ifq_next; |
| } else { |
| /* Nothing on fastq, see if next_m is valid */ |
| if (next_m != &if_batchq) |
| ifm = next_m; |
| else |
| ifm = if_batchq.ifq_next; |
| |
| /* Set which packet to send on next iteration */ |
| next_m = ifm->ifq_next; |
| } |
| /* Remove it from the queue */ |
| ifqt = ifm->ifq_prev; |
| remque(ifm); |
| --if_queued; |
| |
| /* If there are more packets for this session, re-queue them */ |
| if (ifm->ifs_next != /* ifm->ifs_prev != */ ifm) { |
| insque(ifm->ifs_next, ifqt); |
| ifs_remque(ifm); |
| } |
| |
| /* Update so_queued */ |
| if (ifm->ifq_so) { |
| if (--ifm->ifq_so->so_queued == 0) |
| /* If there's no more queued, reset nqueued */ |
| ifm->ifq_so->so_nqueued = 0; |
| } |
| |
| /* Encapsulate the packet for sending */ |
| if_encap(ifm->m_data, ifm->m_len); |
| |
| m_free(ifm); |
| |
| if (if_queued) |
| goto again; |
| } |