Ilias Apalodimas(apalos) replied on github web page:

platform/linux-generic/odp_packet_io.c
line 237
@@ -89,6 +96,274 @@ int odp_pktio_init_local(void)
        return odp_pktio_ops_init_local(true);
 }
 
+static int write_pcapng_hdr(pktio_entry_t *entry, int qidx)
+{
+       size_t len;
+       pcapng_section_hdr_block_t shb;
+       pcapng_interface_description_block_s idb;
+       int fd = entry->s.pcapng_info.pcapng_fd[qidx];
+
+       memset(&shb, 0, sizeof(shb));
+       memset(&idb, 0, sizeof(idb));
+
+       shb.block_type = PCAPNG_BLOCK_TYPE_SHB;
+       shb.block_total_length = sizeof(shb);
+       shb.block_total_length2 = sizeof(shb);
+       shb.magic = PCAPNG_ENDIAN_MAGIC;
+       shb.version_major = 0x1;
+       shb.version_minor = 0x0;
+       shb.section_len = -1;
+
+       len = write(fd, &shb, sizeof(shb));
+       fsync(fd);
+       /* fail to write shb/idb means the pcapng is unreadable */
+       if (!len) {
+               ODP_ERR("Failed to write pcapng section hdr\n");
+               close(fd);
+               return -1;
+       }
+
+       idb.block_type = PCAPNG_BLOCK_TYPE_IDB;
+       idb.block_total_length = sizeof(idb);
+       idb.block_total_length2 = sizeof(idb);
+       idb.linktype = 0x1; /* LINKTYPE_ETHERNET */
+       idb.snaplen = 0x0; /* unlimited */
+       len = write(fd, &idb, sizeof(idb));
+       if (!len) {
+               ODP_ERR("Failed to write pcapng interface description\n");
+               close(fd);
+               return -1;
+       }
+       fsync(fd);
+
+       entry->s.pcapng_info.state[qidx] = PCAPNG_WR_HDR;
+
+       return 0;
+}
+
+static int write_pcapng_pkts(pktio_entry_t *entry, int qidx,
+                            const odp_packet_t packets[], int num)
+{
+       int i = 0;
+       struct iovec packet_iov[3 * num];
+       pcapng_enhanced_packet_block_t epb;
+       int iovcnt = 0;
+       ssize_t len = 0;
+       int fd = entry->s.pcapng_info.pcapng_fd[qidx];
+
+       for (i = 0; i < num; i++) {
+               odp_packet_hdr_t *pkt_hdr = odp_packet_hdr(packets[i]);
+               uint32_t pkt_len = _odp_packet_len(packets[i]);
+               char *buf = (char *)odp_packet_data(packets[i]);
+
+               epb.block_type = PCAPNG_BLOCK_TYPE_EPB;
+               epb.block_total_length = sizeof(epb) +
+                       ROUNDUP_ALIGN(pkt_len, PCAP_DATA_ALIGN) +
+                       PCAP_DATA_ALIGN;
+               epb.interface_idx = 0;
+               epb.timestamp_high = (uint32_t)(pkt_hdr->timestamp.u64 >> 32);
+               epb.timestamp_low = (uint32_t)(pkt_hdr->timestamp.u64);
+               epb.captured_len = pkt_len;
+               epb.packet_len = pkt_len;
+
+               /* epb */
+               packet_iov[iovcnt].iov_base = &epb;
+               packet_iov[iovcnt].iov_len = sizeof(epb);
+               iovcnt++;
+
+               /* data */
+               packet_iov[iovcnt].iov_base = buf;
+               packet_iov[iovcnt].iov_len =
+                       ROUNDUP_ALIGN(pkt_len, PCAP_DATA_ALIGN);
+               iovcnt++;
+
+               /* trailing */
+               packet_iov[iovcnt].iov_base = &epb.block_total_length;
+               packet_iov[iovcnt].iov_len = sizeof(uint32_t);
+               iovcnt++;
+       }
+
+       /* we don't really care if we manage to write *all* data */
+       len = writev(fd, packet_iov, iovcnt);
+       if (!len)
+               ODP_ERR("Failed to write pcapng data\n");
+       fsync(fd);
+
+       return len;
+}
+
+static void pcapng_drain_fifo(int fd)
+{
+       char c;
+       ssize_t len;
+
+       do {
+               len = read(fd, &c, sizeof(c));
+       } while (len > 0 && len != -1);
+       ODP_DBG("Drain pcap fifo %d\n", len);
+}
+
+static void *inotify_update(void *arg)
+{
+       pktio_entry_t *entry = (pktio_entry_t *)arg;
+       struct timeval time;
+       int ret;
+       ssize_t rdlen;
+       int i;
+       char buffer[INOTIFY_BUF_LEN];
+       unsigned int max_queue =
+               MAX(entry->s.num_in_queue, entry->s.num_out_queue);
+       fd_set rfds;
+
+       while (1) {
+               i = 0;
+               FD_ZERO(&rfds);
+               FD_SET(entry->s.pcapng_info.inotify_pcapng_fd, &rfds);
+               time.tv_sec = 2;
+               time.tv_usec = 0;
+               select(entry->s.pcapng_info.inotify_pcapng_fd + 1, &rfds, NULL,
+                      NULL, &time);
+               if (FD_ISSET(entry->s.pcapng_info.inotify_pcapng_fd, &rfds)) {
+                       rdlen = read(entry->s.pcapng_info.inotify_pcapng_fd,
+                                    buffer, INOTIFY_BUF_LEN);
+                       while (i < rdlen) {
+                               char *e;
+                               unsigned int qidx;
+                               struct inotify_event *event =
+                                       (struct inotify_event *)(void *)
+                                        &buffer[i];
+
+                               e = strrchr(event->name, '-');
+                               e++;
+                               if (!e)
+                                       continue;
+                               qidx = atoi(e);
+                               if (qidx > max_queue) {
+                                       ODP_ERR("Invalid queue number\n");
+                                       i += INOTIFY_EVENT_SIZE + event->len;
+                                       continue;
+                               }
+
+                               if (entry->s.pcapng_info.state[qidx] ==
+                                   PCAPNG_WR_INVALID)
+                                       continue;
+
+                               if (event->mask & IN_OPEN) {
+                                       int fd = 
entry->s.pcapng_info.pcapng_fd[qidx];
+
+                                       pcapng_drain_fifo(fd);
+                                       ret = write_pcapng_hdr(entry, i);
+                                       if (ret)
+                                               
entry->s.pcapng_info.state[qidx] =
+                                                       PCAPNG_WR_STOP;
+                                       else
+                                               
entry->s.pcapng_info.state[qidx] =
+                                                       PCAPNG_WR_PKT;
+                                       ODP_DBG("Open %s for pcap tracing\n",
+                                               event->name);
+                               } else if (event->mask & IN_CLOSE) {
+                                       entry->s.pcapng_info.state[qidx] =
+                                               PCAPNG_WR_STOP;
+                                       ODP_DBG("Close %s for pcap tracing\n",
+                                               event->name);
+                               } else {
+                                       ODP_ERR("Unknown inotify event 
0x%08x\n",
+                                               event->mask);
+                               }
+                               i += INOTIFY_EVENT_SIZE + event->len;
+                       }
+               }
+       }
+
+       return NULL;
+}
+
+static void pcapng_destroy(pktio_entry_t *entry)
+{
+       int ret;
+       unsigned int i;
+       unsigned int max_queue =
+               MAX(entry->s.num_in_queue, entry->s.num_out_queue);
+
+       ret = pthread_cancel(entry->s.pcapng_info.inotify_thread);
+       if (ret)
+               ODP_ERR("can't cancel inotify thread %s\n", strerror(errno));
+
+       /* fd's will be -1 in case of any failure */
+       ret = inotify_rm_watch(entry->s.pcapng_info.inotify_pcapng_fd,
+                              entry->s.pcapng_info.inotify_watch_fd);
+       if (ret)
+               ODP_ERR("can't deregister inotify %s\n", strerror(errno));
+
+       close(entry->s.pcapng_info.inotify_pcapng_fd);
+
+       for (i = 0; i < max_queue; i++) {
+               entry->s.pcapng_info.state[i] = PCAPNG_WR_INVALID;
+               close(entry->s.pcapng_info.pcapng_fd[i]);
+       }
+}
+
+static int pcapng_prepare(pktio_entry_t *entry)
+{
+       int ret = -1, fd;
+       pthread_attr_t attr;
+       unsigned int i;
+       unsigned int max_queue =
+               MAX(entry->s.num_in_queue, entry->s.num_out_queue);
+
+       for (i = 0; i < max_queue; i++) {
+               char pcap_entry[256];
+
+               snprintf(pcap_entry, sizeof(pcap_entry),
+                        "%s/%s-flow-%d", PCAPNG_WATCH_DIR, entry->s.name, i);


Comment:
will update

> Ilias Apalodimas(apalos) wrote:
> This essentially "reads" the inotify triggers for opening/closing the fifos 
> and sets the appropriate variables for starting/stopping the pcapng dump on 
> fifos. Will try to make it easier to read on the final PR


>> Ilias Apalodimas(apalos) wrote:
>> will fix


>>> Ilias Apalodimas(apalos) wrote:
>>> will fix


>>>> Ilias Apalodimas(apalos) wrote:
>>>> I'll check and update for the final PR


>>>>> Bill Fischofer(Bill-Fischofer-Linaro) wrote:
>>>>> General cleanup should be part of `odp_term_global()` processing. 
>>>>> Presumably `odp_pktio_close()` should also do cleanup for specific pktios.


>>>>>> Bill Fischofer(Bill-Fischofer-Linaro) wrote:
>>>>>> A few comments about what this routine is doing would be very helpful 
>>>>>> here. This is not easy code to follow. Modularizing it into some  
>>>>>> `static inline` helpers might also make the logic simpler.


>>>>>>> Bill Fischofer(Bill-Fischofer-Linaro) wrote:
>>>>>>> This is redundant. If `len > 0` then by definition `len != -1`.


>>>>>>>> Bill Fischofer(Bill-Fischofer-Linaro) wrote:
>>>>>>>> This fails for multi-segment packets. `odp_packet_data(pkt)` is 
>>>>>>>> shorthand for `odp_packet_offset(pkt, 0, NULL, NULL)` so you don't 
>>>>>>>> know how long the first segment really is. First cut would be to only 
>>>>>>>> dump the first segment, so correct code is:
>>>>>>>> ```
>>>>>>>> uint32_t seg_len;
>>>>>>>> char *buf = (char *)odp_packet_offset(packets[i], 0, &seg_len, NULL);
>>>>>>>> ```
>>>>>>>> And use `seg_len` rather than `pkt_len` in this routine.


>>>>>>>>> Bill Fischofer(Bill-Fischofer-Linaro) wrote:
>>>>>>>>> Does pcapng not supply a `.h` file for these "magic numbers" and 
>>>>>>>>> associated structs?


>>>>>>>>>> Ilias Apalodimas(apalos) wrote:
>>>>>>>>>> Will fix. This will also remove the requirement of manually deleting 
>>>>>>>>>> the fifos


>>>>>>>>>>> muvarov wrote
>>>>>>>>>>> odp_global_data_s->main_pid needs to be here.


https://github.com/Linaro/odp/pull/435#discussion_r165572186
updated_at 2018-02-02 07:15:58

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