Understanding Linux Network Internals 
by Christian Benvenuti

This errata page lists errors corrected in the 5/08 printing.

Here's a key to the markup:
	[page-number]: serious technical mistake
	{page-number}: minor technical mistake
	<page-number>: important language/formatting problem
	(page-number): language change or minor formatting problem
	?page-number?: reader question or request for clarification


(14)  3rd par
Because of the waste cause by looping ...
should be
Because of the waste caused by looping ...


[39] code line above "Cloning and copying buffers"
skb_shinfo(skb)->dataref++;
should be
skb_shinfo(skb)->nr_frags++;


{40}  Figure 2-9;
Interchange sk_shinfo(clone) and sk_shinfo(skb


(42)   Code at bottom of page;
___function_name
should be
__function_name


[47]   unsigned char addr_len, line 3;
Ethernet addresses are 6 octets long. 
8 
should be: 
6


(51)  3rd paragraph;
all_multi
should be
allmulti


(57)  figure 2-11;
One of the directories, listed in the figure reads "kernal", but that
should be "kernel".


(68)  Figure 3-3;
sysctel_jiffies should be sysctl_jiffies
sysctel_local_port_range should be sysctl_local_port_range
sysct1_local_port_range should be sysctl_local_port_range 


(69)  Figure 3-4;
SIOC S DEL DLCI should be SIOC DEL DLCI


{76}  Figure 4-2;
The connection from Network A to Network F is not shown.There is one line missing between Network F
and Network A (it would be a line like the one between Network E
and Network F).


(93)  First call of module_param();
module_param(multicast_filter_limit, int 0444);
should be
module_param(multicast_filter_limit, int, 0444);


(97)  Figure 5-3.;
request_model should be request_module.
Under request_module, arg[i] should be arg[1].
Under /sbin/modprobe, insmod3c59x should be "insmod 3c59x".


(98)  kmod bullet 1 line 4;
prorobe.conf should be modprobe.conf.


(131)  12th line from the bottom;
However, a few architectures discard it a runtime...
should be
However, a few architectures discard it at runtime...


{140}  Figure 8-1 (a);
the second call of alloc_etherdev() should be alloc_netdev()


(144)  Footnote +;
In line 2, "habit" should be "habitat".


(150)  Split Operations: netdev_run_todo last line of first paragraph after head;
reference to Figure 8-4 should be 8-5(a)


(150)  Figure 8-4;
dev->unit should be dev->uninit
"dev->destruct or" should be dev->destructor


(160)  Figure 8-6;
The transision
  [Send notification]-><Any linkwatch event pending on the device>
should not be labeled with the word "no."


(164)  Figure 8-7;
kevent_wq
should be
keventd_wq


(167)  Figure 8-8;
The second ocurrence of SIOCGMIIREG should be SIOCSMIIREG
The first ocurrence of SIOCGMIIRG should be SIOCGMIIREG
The second ocurrence of SIOCGMIIRG should be SIOCSMIIREG


(168)  Last line of first paragraph;
8-9 should be 8-8.


(178)  Line 2 of paragraph 3;
"the does" should be "does".



{183}  2nd paragraph;
"vortex_interrupt keeps processing incoming frames until the register says..." should
be "vortex_interrupt keeps processing incoming frames as long as the register
says..."


(192)  do_IRQ line 3;
"transmission" should be "execution"


(194)  raise_softirq_irqoff line 1;
__cpu_raise_softirq should be __raise_softirq_irqoff


{195}  line 30 (including lines of code);
"(there are no softirqs pending, etc.)"
should be:
"(there are softirqs pending, etc.)"


(204)  Talklet Processing, line 1;
"low-latency" should be "low-priority".
"high-latency" should be "high-priority".


{209}  First line of last paragraph.;
softnet_data->blog_dev
should be
softnet_data.backlog_dev


(211)  Line 3 of last paragraph.;
open
should be
opened


(216)  Figure 10-1;
_LINK_STATE_RX_SCHED
should be
__LINK_STATE_RX_SCHED


(220) in Figure 10-3 
NETROLL should be NETPOLL

and

Move cpu out of the throttling stats
should be
Move cpu out of the throttling state


(233)  Figure 10-6;
refont
should be
reference count


(232)  First line of last paragraph.;
dev->quota
should be
backlog_dev->quota


(237)  Line 4 of fourth paragraph from the bottom;
above
should be
upper


(238)  bullet 1;
L4
should be
L3


(240)  Figure 11-1 (a);
(__LINK_STATE_RX_SCHED))
should be
(__LINK_STATE_RX_SCHED)


(240)  Figure 11-1 (b):
engress
should be
egress


{244}  1st paragraph;
.., output_queue is used by both NAPI and non-NAPI devices, and poll_list is used
only to handle NON-NAPI devices
should be
.., output_queue is used by both NAPI and non-NAPI devices, and poll_list is used 
only to handle NAPI devices


[250] 2nd bullet in middle of page;
"In this case, the function does not actually fail, but generates a warning with a call to BUG()"
should be
"In this case, the BUG macro is invoked, leading to a kernel panic"


(254)  Figure 11-4 (b);
netif_x
should be
netif_rx


(268)  5th(?) paragraph - near middle of the page;
In "...and Ethereal are common users of AF_SOCKET sockets.", AF_SOCKET should be
AF_PACKET


[273]  Figure 13-4 (occurs twice in figure);
Dst MAC-00:20....
should be
Dst MAC=00:20... 


(281)  Last line of last paragraph;
isdiscussed
should be
is discussed


(283)  Figure 13-8 (a), Protocol field;
1534
should be
1536


(284)  last paragraph (above 1st bullet);
"The two most significant bits of the first byte..." should read "The two least
significant bits of the first byte..."


(305)  3rd paragraph;
In the sentence "...from Bridge 1's perspective, Hosts A, B, C and D are all located
in LAN2,..." 
Bridge 1
should be:
Bridge 2


(308)  Last paragraph, line 5.;
14-8
should be
14-9


{324}  Figure 15-8(b) caption.;
BPDU
should be
TCN BPDU


(347)  Ingress BPDUs, paragraph 2, line 2.;
Figure 15-7
should be
Figure 15-8


(351)  2nd-to-last bullet, line 2;
old, disabled
should be
old disabled


(361)  Paragraph 1, line 3.;
Ethernel
should be
Ethernet


(371)  Figure 16-11;
ENGRESS
should be
EGRESS


(377)  Figure 16-12;
E thernet
should be
Ethernet


(385)  br_transmit_config line 2;
...in Chapter 15."
should be
...in Chapter 15.


{390}  NETDEV_UP, line 2.;
br_stp_enabled_port
should be
br_stp_enable_port


{395}  Table 17-3, argument for showstp;
BRCTL_SET_BRIDGE_INFO
should be
BRCTL_GET_BRIDGE_INFO


{397}  CLASS_DEV_ATTR line;
S_IURGO
should be
S_IRUGO


{398}  BRPORT_ATTR line;
S_IURGO
should be
S_IRUGO


(432)  Checksums, line 2;
Some checksums cannot only detect errors...
should be
Some checksums can not only detect errors...


(444)  third bullet from the top;
(see the section ?Long-Living IP Peer Information? in Chapter 23.
should be
(see the section ?Long-Living IP Peer Information? in Chapter 23).


[451]  line 1 and 2;
'See the section "Local Delivery" in Chapter 20 
should be
...in Chapter 35


{452}  Paragraph 2, line 2.;
ip_option
should be
ip_options


{471}  ip_forward_finish line 5;
if (unlikely(opt->optlen) {
should be
if (unlikely(opt->optlen) )


(490)  Figure 21-7;
X+S1+S2<+PMTU
should be
X+S1+S2<=PMTU


(491)  Figure 21-8;
dala_len
should be
data_len


(493)  Further handling of the buffers, paragraph 1, line3;
sw_write_queue
should be
sk_write_queue


(500)  Figure 21-11.;
MSG_MOER
should be
MSG_MORE


(506)  Figure 21-12(b);
ip_push_peinding_frames caller
should be
ip_push_peinding_frame's caller


(517)  Line 1 of 3rd displayed block of code;
sk2
should be
skb2


(524)  Line4 from the bottom;
Last Recently Used (LRU)
should be
Least Recently Used (LRU)


(531)  Last  line above Figure 22-2.;
both F3 and F4 (which is completely included).
should be
both F3 (which is completely included) and F4.


(536)  Last line of paragraph 2;
base
should be
basis


{537}  Line 5 of bullet 2.;
the most recently used
should be
the least recently used


(539)  Figure 23-1;
Delete the "No" above "Is the Create flag set?", and add a "Yes" below.


(542)  Paragraph 2, line 3.;
IPSTATS_MIX_XXX
should be
IPSTATS_MIB_XXX


(553)  Table 23-2;
ipfrag_high_tresh
should be
ipfrag_high_thresh 

and

ipfrag_low_tresh
should be
ipfrag_low_thresh


(556)  Figure 23-3;
skhuff.h
should be
skbuff.h


(577)  Paragraph 2, line 7.;
The figure also shows that...
should be
Figure 24-4 also shows that...


(581)  Paragraph 4, line 8.;
traceroute, which needs to plays with...
should be
traceroute, which needs to play with...


(581)  Last paragraph, line 1.;
...and the ones used to store...
should be
...and the one used to store...


(592)  Bottom of page;
Add:
5. Router RT2 forwards the packet to Host Y.


(592)  Figure 25-3;
(2) should be (3)
(3) should be (4)
(4) should be (5)
Add (2) to the right of the icon for Router RT1.


{593}  ICMP_TIME_EXCEEDED paragraph 2, line 3.;
The intermediate host that drops the packet...
should be
The intermediate router that drops the packet...


(610)  Paragraph 2, line 1;
xlim_allow
should be
xrlim_allow


(615)  Figure 25-13;
Low Warning Message
should be
Log Warning Message


(615)  Figure 25-13;
Delete the "Yes" on the arrow out of [Deliver ICMP to raw IP sockets].


(619)  ICMP_MIB_INXXX, ICMP_MIB_OUTXXX;
there is one per-ICMP
should be
there is one per ICMP


(631)  Line 3.;
CMSA/CD
should be
CSMA/CD


(658)  Paragraph 4, line 4.;
"Figure 26-12" should be "Figure 26-13".


{658}  Figure 27-4;
The arrow pointing from NUD_STALE to NUD_REACHABLE should actually point the other
way around (from NUD_REACHABLE to NUD_STALE).


(661)  Last line.;
the section "Final Common Processing in Chapter 28).
should be
the section "Final Common Processing" in Chapter 28).


(662)  2nd line
NEIGH_UPDATE_ISROUTER
Should be
NEIGH_UPDATE_F_ISROUTER


(663)  Figure 27-5(a), block b.;
NUD_VALUE
should be
NUD_VALID


(681)  Figure 27-9, top left;
Form?
should be
From?


(681)  Figure 27-9, lower middle;
proxy_len
should be
proxy_qlen


[692]  5th paragraph, 1st sentence;
"The input skb buffer, ip_finish_output2, includes the packet data..." should read
"The skb buffer input to ip_finish_output2, includes the packet data..." or "The
input skb buffer includes the packet data..."


(694)  Figure 27-13(a), lower left;
dst->hh (neigh hh init)
should be
dst->hh (neigh_hh_init)


(707)  Figure 28-5 (error occurs in three places);
AROP_
should be
ARPOP_


(712)  First line of last paragraph.;
HostC
should be
Host C


(721)  Last line of first displayed source code.;
Delete the final #endif


(742)  Bullet (b), line 1 of paragraph 2;
A2
should be
A


(742)  Bullet (b), line 3 of paragraph 3.;
accordingly to
should be
according to


(744)  ARPD, line 3.;
system performances
should be
system performance


(745)  First entry under Kernel Side;
neigh_apps_ns
should be
neigh_app_ns


(745)  Figure 28-22 (error occurs in two places);
RTN_
should be
RTM_


(747)  Figure 28-23 (error occurs in two places);
RTN_
should be RTM_


(759)  unsigned long confirmed, last line.;
...described in .
should be
...described in "Updating a Neighbor's Information: neigh_update" in Chapter 27.


(762)  int entry_size, line 2.;
...includes a field whose size depends on the protocol (primary_key),
should be
...includes a field (primary_key) whose size depends on the protocol,


(813) Figure 31-5(c);
In the last line of the ip route add command, 10.0.0.2.1 should be 10.0.2.1


(849) Figure 32-6.;
The No branch of "Have all next hops been marked DEAD?" is not labeled.


(885) First line.;
"is" should be "is not".


(893) Bullet 2, line 4.;
"any" should be "an".


(898) Bullet 4, line 1.;
"indegiven" should be "given".


(934) Figure 35-8(b) caption.;
p_route_output_slow should be ip_route_output_slow.


(961) Footnote +, line 5.;
"where as" should be "whereas".


(982) metrics, paragraph 2, line 3.;
"options" should be "option".