func MakeSnapShot()

in pkg/tcp_metrics/parser/parse.go [80:134]
51 lines of code
15 McCabe index (conditional complexity)

func MakeSnapShot(msg *NetlinkMessage, skipLocal bool) (*Snapshot, error) {
	if msg.Header.Type != 20 {
		return nil, ErrNotType20
	}

	raw, attrBytes := inetdiag.SplitInetDiagMsg(msg.Data)
	if raw == nil {
		return nil, ErrParseFailed
	}
	if skipLocal {
		idm, err := raw.Parse()
		if err != nil {
			return nil, err
		}

		if isLocal(idm.ID.SrcIP()) || isLocal(idm.ID.DstIP()) {
			return nil, nil
		}
	}

	attrsUnsafe, err := ParseRouteAttr(attrBytes)
	if err != nil {
		return nil, err
	}
	maxAttrType := uint16(0)
	for _, a := range attrsUnsafe {
		t := a.Attr.Type
		if t > maxAttrType {
			maxAttrType = t
		}
	}
	if maxAttrType > 2*inetdiag.INET_DIAG_MAX {
		maxAttrType = 2 * inetdiag.INET_DIAG_MAX
	}
	attributes := make([][]byte, maxAttrType+1, maxAttrType+1)
	for _, a := range attrsUnsafe {
		t := a.Attr.Type
		if t > maxAttrType {
			fmt.Println("Error!! Received RouteAttr with very large Type:", t)
			continue
		}
		if attributes[t] != nil {
			// TODO - add metric so we can alert on these.
			fmt.Println("Parse error - Attribute appears more than once:", t)
		}
		attributes[t] = a.Value
	}
	snp, err := decode(&raw, attributes)
	if err != nil {
		return nil, err
	}
	sockInfo := snp.InetDiagMsg.ID.GetSockID()
	snp.SockInfo = &sockInfo
	return snp, nil
}