diff options
| -rw-r--r-- | pcap-int.h | 2 | ||||
| -rw-r--r-- | pcap-linux.c | 49 | ||||
| -rw-r--r-- | pcap-usb-linux.c | 16 |
3 files changed, 33 insertions, 34 deletions
@@ -133,6 +133,8 @@ struct pcap_md { u_int packets_read; /* count of packets read with recvfrom() */ bpf_u_int32 oldmode; /* mode to restore when turning monitor mode off */ char *mondevice; /* mac80211 monitor device we created */ + u_char *mmapbuf; /* memory-mapped region pointer */ + size_t mmapbuflen; /* size of region */ u_int tp_version; /* version of tpacket_hdr for mmaped ring */ u_int tp_hdrlen; /* hdrlen of tpacket_hdr for mmaped ring */ #endif /* linux */ diff --git a/pcap-linux.c b/pcap-linux.c index 4165eba0..631ef328 100644 --- a/pcap-linux.c +++ b/pcap-linux.c @@ -2574,20 +2574,6 @@ prepare_tpacket_socket(pcap_t *handle) return 1; } -static void -compute_ring_block(int frame_size, unsigned *block_size, unsigned *frames_per_block) -{ - /* compute the minumum block size that will handle this frame. - * The block has to be page size aligned. - * The max block size allowed by the kernel is arch-dependent and - * it's not explicitly checked here. */ - *block_size = getpagesize(); - while (*block_size < frame_size) - *block_size <<= 1; - - *frames_per_block = *block_size/frame_size; -} - static int create_ring(pcap_t *handle) { @@ -2603,7 +2589,17 @@ create_ring(pcap_t *handle) TPACKET_ALIGN(handle->md.tp_hdrlen) + sizeof(struct sockaddr_ll)); req.tp_frame_nr = handle->opt.buffer_size/req.tp_frame_size; - compute_ring_block(req.tp_frame_size, &req.tp_block_size, &frames_per_block); + + /* compute the minumum block size that will handle this frame. + * The block has to be page size aligned. + * The max block size allowed by the kernel is arch-dependent and + * it's not explicitly checked here. */ + req.tp_block_size = getpagesize(); + while (req.tp_block_size < req.tp_frame_size) + req.tp_block_size <<= 1; + + frames_per_block = req.tp_block_size/req.tp_frame_size; + req.tp_block_nr = req.tp_frame_nr / frames_per_block; /* req.tp_frame_nr is requested to match frames_per_block*req.tp_block_nr */ @@ -2632,10 +2628,11 @@ retry: } /* memory map the rx ring */ - ringsize = req.tp_block_nr * req.tp_block_size; - handle->bp = mmap(0, ringsize, PROT_READ| PROT_WRITE, MAP_SHARED, - handle->fd, 0); - if (handle->bp == MAP_FAILED) { + handle->md.mmapbuflen = req.tp_block_nr * req.tp_block_size; + ringsize = handle->md.mmapbuflen; + handle->md.mmapbuf = mmap(0, handle->md.mmapbuflen, + PROT_READ|PROT_WRITE, MAP_SHARED, handle->fd, 0); + if (handle->md.mmapbuf == MAP_FAILED) { snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "can't mmap rx ring: %s", pcap_strerror(errno)); @@ -2659,7 +2656,7 @@ retry: /* fill the header ring with proper frame ptr*/ handle->offset = 0; for (i=0; i<req.tp_block_nr; ++i) { - void *base = &handle->bp[i*req.tp_block_size]; + void *base = &handle->md.mmapbuf[i*req.tp_block_size]; for (j=0; j<frames_per_block; ++j, ++handle->offset) { RING_GET_FRAME(handle) = base; base += req.tp_frame_size; @@ -2682,14 +2679,10 @@ destroy_ring(pcap_t *handle) (void *) &req, sizeof(req)); /* if ring is mapped, unmap it*/ - if (handle->bp) { - /* need to re-compute the ring size */ - unsigned frames_per_block, block_size; - compute_ring_block(handle->bufsize, &block_size, &frames_per_block); - - /* do not perform sanity check here: we can't recover any error */ - munmap(handle->bp, block_size * handle->cc / frames_per_block); - handle->bp = 0; + if (handle->md.mmapbuf) { + /* do not test for mmap failure, as we can't recover from any error */ + munmap(handle->md.mmapbuf, handle->md.mmapbuflen); + handle->md.mmapbuf = NULL; } } diff --git a/pcap-usb-linux.c b/pcap-usb-linux.c index 3d7cb2c5..ab30159e 100644 --- a/pcap-usb-linux.c +++ b/pcap-usb-linux.c @@ -201,8 +201,10 @@ int usb_mmap(pcap_t* handle) if (len < 0) return 0; - handle->buffer = mmap(0, len, PROT_READ, MAP_SHARED, handle->fd, 0); - return handle->buffer != MAP_FAILED; + handle->md.mmapbuflen = len; + handle->md.mmapbuf = mmap(0, handle->md.mmapbuflen, PROT_READ, + MAP_SHARED, handle->fd, 0); + return handle->md.mmapbuf != MAP_FAILED; } #define CTRL_TIMEOUT (5*1000) /* milliseconds */ @@ -799,7 +801,7 @@ usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_ch nflush = fetch.nfetch; for (i=0; i<fetch.nfetch; ++i) { /* discard filler */ - hdr = (pcap_usb_header*) &handle->buffer[vec[i]]; + hdr = (pcap_usb_header*) &handle->md.mmapbuf[vec[i]]; if (hdr->event_type == '@') continue; @@ -833,8 +835,10 @@ usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_ch static void usb_cleanup_linux_mmap(pcap_t* handle) { - /* buffer must not be freed because it's memory mapped */ - /* XXX - does it need to be unmapped? */ - handle->buffer = NULL; + /* if we have a memory-mapped buffer, unmap it */ + if (handle->md.mmapbuf != NULL) { + munmap(handle->md.mmapbuf, handle->md.mmapbuflen); + handle->md.mmapbuf = NULL; + } pcap_cleanup_live_common(handle); } |