server/mailet/mailets/src/main/java/org/apache/james/transport/mailets/SPF.java

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package org.apache.james.transport.mailets;

import java.util.Collection;

import javax.inject.Inject;
import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;

import org.apache.james.dnsservice.api.DNSService;
import org.apache.james.dnsservice.library.netmatcher.NetMatcher;
import org.apache.james.jspf.executor.SPFResult;
import org.apache.james.jspf.impl.DefaultSPF;
import org.apache.mailet.Attribute;
import org.apache.mailet.AttributeName;
import org.apache.mailet.AttributeUtils;
import org.apache.mailet.AttributeValue;
import org.apache.mailet.Experimental;
import org.apache.mailet.Mail;
import org.apache.mailet.base.GenericMailet;
import org.slf4j.LoggerFactory;

import com.google.common.base.Splitter;

/**
 * Check the ip, sender, helo against SPF. Add the following attributes to the
 * mail object:
 * 
 * <pre>
 * <code>
 *  org.apache.james.transport.mailets.spf.explanation
 *  org.apache.james.transport.mailets.spf.result
 * </code>
 * </pre>
 * 
 * Sample configuration:
 * 
 * <pre>
 * &lt;mailet match="All" class="SPF"&gt;
 *   &lt;addHeader&gt;true&lt;/addHeader&gt;
 *   &lt;debug&gt;false&lt;/debug&gt;
 *   &lt;ignoredNetworks&gt;127.0.0.0/8&lt;/ignoredNetworks&gt;
 * &lt;/mailet&gt;
 * </pre>
 */
@Experimental
public class SPF extends GenericMailet {
    private static final org.slf4j.Logger LOGGER = LoggerFactory.getLogger(SPF.class);

    private boolean debug = false;
    private boolean addHeader = false;
    private org.apache.james.jspf.impl.SPF spf;
    public static final AttributeName EXPLANATION_ATTRIBUTE = AttributeName.of("org.apache.james.transport.mailets.spf.explanation");
    public static final AttributeName RESULT_ATTRIBUTE = AttributeName.of("org.apache.james.transport.mailets.spf.result");
    private static final String privateNetworks = "127.0.0.0/8, 10.0.0.0/8, 172.16.0.0/16, 172.17.0.0/16, 172.18.0.0/16, 172.19.0.0/16, 172.20.0.0/16, 172.21.0.0/16, 172.22.0.0/16, 172.23.0.0/16, 172.24.0.0/16, 172.25.0.0/16, 172.26.0.0/16, 172.27.0.0/16, 172.28.0.0/16, 172.29.0.0/16, 172.30.0.0/16, 172.31.0.0/16";

    private final DNSService dnsService;
    private NetMatcher netMatcher;

    // should be removed in future (see JAMES-2158)
    private org.apache.james.jspf.core.DNSService spfDnsService;

    @Inject
    public SPF(DNSService dnsService) {
        this.dnsService = dnsService;
    }

    public void setSPFDnsService(org.apache.james.jspf.core.DNSService spfDnsService) {
        this.spfDnsService = spfDnsService;
    }

    @Override
    public void init() {
        debug = Boolean.parseBoolean(getInitParameter("debug", "false"));
        addHeader = Boolean.parseBoolean(getInitParameter("addHeader", "false"));

        if (spfDnsService == null) {
            spf = new DefaultSPF();
        } else {
            spf = new org.apache.james.jspf.impl.SPF(spfDnsService);
        }

        Collection<String> ignoredNetworks = Splitter.on(',')
            .trimResults()
            .omitEmptyStrings()
            .splitToList(getInitParameter("ignoredNetworks", privateNetworks));
        netMatcher = new NetMatcher(ignoredNetworks, dnsService);

        LOGGER.info("SPF addHeader={} debug={} ignoredNetworks={}", addHeader, debug, ignoredNetworks);
    }

    @Override
    public void service(Mail mail) throws MessagingException {
        String remoteAddr = mail.getRemoteAddr();

        if (netMatcher.matchInetNetwork(remoteAddr)) {
            LOGGER.debug("ignore SPF check for ip:{}", remoteAddr);
        } else {
            String helo = AttributeUtils.getValueAndCastFromMail(mail, Mail.SMTP_HELO, String.class).orElse(mail.getRemoteHost());
            String sender = mail.getMaybeSender().asString("");
            SPFResult result = spf.checkSPF(remoteAddr, sender, helo);
            mail.setAttribute(new Attribute(EXPLANATION_ATTRIBUTE, AttributeValue.of(result.getExplanation())));
            mail.setAttribute(new Attribute(RESULT_ATTRIBUTE, AttributeValue.of(result.getResult())));

            LOGGER.debug("ip:{} from:{} helo:{} = {}", remoteAddr, sender, helo, result.getResult());
            if (addHeader) {
                try {
                    MimeMessage msg = mail.getMessage();
                    msg.addHeader(result.getHeaderName(), result.getHeaderText());
                    msg.saveChanges();
                } catch (MessagingException e) {
                    // Ignore not be able to add headers
                }
            }
        }
    }
}