Bill Fischofer(Bill-Fischofer-Linaro) replied on github web page:

platform/linux-generic/odp_packet_io.c
line 121
@@ -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);


Comment:
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_r165548254
updated_at 2018-02-02 03:09:47

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