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最近需要分析PCAP文件，主要是用WireShark 来打开PCAP文件，用 winpcap库来解析PCAP文件。因为经常使用MATLAB ,就尝试找了找MATLAB解析PCAP文件的方法。找到了几个能解析PCAP文件的matlab开源项目pcap2matlab。下载地址：http://download.csdn.net/download/sunboyiris/9951242
该项目解析如下：
打开pcap2matlab_example.m ，代码如下，点击运行：
function pcap2matlab_example()
isRead = true;
CAPTURE_FILE = 'gigE_image.pcapng';
%% Set up the capturing/reading parameters:
dissector = {'gvsp.status',...
'gvsp.blockid16',...
'gvsp.format',...
'gvsp.packetid24',...
'gvsp.fieldid',...
'gvsp.fieldcount',...
'gvsp.timestamp',...
'gvsp.pixel.color','gvsp.pixel.occupy','gvsp.pixel.id',...
'gvsp.sizex','gvsp.sizey',...
'gvsp.offsetx','gvsp.offsety',...
'gvsp.paddingx','gvsp.paddingy',...
'gvsp.payloaddata','gvsp.payloadtype'};
capture_filter = 'udp and src port 20202';
read_filter = 'gvsp';
%% Capture/read:
if isRead
% Read:
pcap_result = pcap2matlab(read_filter, dissector, CAPTURE_FILE);
else
% Capture:
pcap_result = pcap2matlab(capture_filter,dissector, 4, 700);
end
%% Verify payload:
PKT_WITH_ERROR = 0; % < not defined in the standard
PKT_FORMAT_LEADER = 1;
PKT_FORMAT_TRAILER = 2;
PKT_FORMAT_PAYLOAD = 3;
% DATA_PAYLOAD_FORMAT_H264 = 5;
% DATA_PAYLOAD_FORMAT_MULTIZONE = 6;
% DATA_ALL_IN_FORMAT = 4;
% Remove packets with errors and sort:
packet_format = vertcat(pcap_result.gvsp_format);
pcap_result = nestedSortStruct(pcap_result(packet_format ~= PKT_WITH_ERROR),...
strrep(dissector([2,4]),'.','_'));
% Make sure we captured full images by discarding partial packets. The
% reason we have a loops is that we want to update {pos_starts, pos_footrs} w/o
% repeating code (DRY principle);
flag = true;
while flag
packet_format = vertcat(pcap_result.gvsp_format);
pos_starts = find(packet_format == PKT_FORMAT_LEADER);
pos_footrs = find(packet_format == PKT_FORMAT_TRAILER);
if numel(pos_starts) == numel(pos_footrs) && ...
all(pos_starts-pos_footrs<0) && numel(pcap_result) == pos_footrs(end)
flag = false; %means we can stop now
else
pcap_result = pcap_result(pos_starts(1):pos_footrs(end));
end
end
% Split the pcap structure into frame-chunks:
if numel(pos_starts) < 1
%this means we have no valid frames
return;
elseif numel(pos_starts) == 1
frames = {pcap_result};
else
frames = arrayfun(@(x)pcap_result(pos_starts(x):pos_footrs(x)),...
1:numel(pos_starts),'un',0);
end
%% Analyze result:
for indF=1:numel(frames)
fr = frames{indF};
% Rebuild image from hex:
pix_vec = single(swapbytes(typecast(uint16(...
... hex_img = [fr([fr.gvsp_format] == 3).gvsp_payloaddata];
sscanf([fr([fr.gvsp_format] == 3).gvsp_payloaddata],...
'%4x')), 'uint16')));
% Remove invalid pixels:
pix_vec(pix_vec > 2^14-1 | ~pix_vec) = NaN; % remove zero & >intmax(uint14)
pc = [prctile(pix_vec,0.01) prctile(pix_vec,99.99)]; % find updated percentiles
pix_vec(pix_vec < pc(1) | pix_vec < pc(1)) = NaN;
% Reshape pixel vector into a 2d image:
img = reshape(pix_vec,fr(1).gvsp_sizex,[]).';
% Plot:
figure();
subplot(2,1,1); imagesc(img); axis image; colorbar; caxis(500*[floor(pc(1)/500) ceil(pc(2)/500)]); colormap(gray(512));
%subplot(2,1,2); histogram(pix_vec,(pc(1):pc(2)+1)-0.5); %alt: numel(unique(img));
end
